Every SEI lower unit is a direct replacement for a specific Mercury OEM gear housing. The reliable way to find yours is to identify your Mercury complete gear-housing part number first, then cross-reference it on our site.

1. Find your engine serial number — it's on the engine's ID/serial tag (transom bracket or powerhead). This is the key that unlocks everything else.
2. Confirm your exact engine model and year on Mercury's owner's-manual page.
3. Open Mercury's Parts Finder and select your engine. Go to the Gear Housing (lower unit) section for your motor.
4. Pick the right part number. The gearcase diagram lists dozens of numbers — seals, bearings, gears, the water pump, individual housings. Ignore those. You want the complete gear housing / lower unit assembly number for the whole unit. If more than one complete assembly is listed, match it to your shaft length, gear ratio, and rotation.
5. Type that OEM assembly number into the search box at the top of seimarine.eu and follow the result to the matching SEI lower unit.
6. Confirm the shaft length and gear ratio on the SEI product page match your engine before you order.

Mercury tacks a letter code onto the end of the model (like a "250XL" or "300CXL") that tells you the shaft length and rotation:

• L (Long) = 20″ shaft
• XL (Extra Long) = 25″ shaft
• XXL (Extra Extra Long) = 30″ shaft
• CXL = Counter-rotation, 25″ shaft
• CXXL = Counter-rotation, 30″ shaft

The "C" always means counter-rotation — the left-hand engine on a twin setup. If your motor has a C in the code, you need a counter-rotation SEI unit; a standard-rotation unit will not work. When in doubt, measure from the mounting surface of the gear housing to the top of the driveshaft splines: roughly 23″ = 20″ shaft, 27–28″ = 25″ shaft, 32–33″ = 30″ shaft. And watch for a spacer — a 25″ shaft with a 5″ spacer can look like a 30″.

Not every Mercury gearcase has an SEI replacement, and it comes down to the propeller shaft:

• FleetMaster (the standard gearcase) uses a 15-spline prop shaft. This is the one SEI makes — our Mercury lower units replace FleetMaster-style gearcases.
• TorqueMaster, TorqueMaster 2, and Sport Master are Mercury's heavy-duty / high-performance gearcases, used on many Pro XS and high-output motors. They use a bigger 19-spline "fat shaft" propeller and a more robust case. SEI does not manufacture a TorqueMaster or Sport Master unit. A standard SEI gearcase can physically bolt up to some of these, but the prop shaft is smaller (it needs a hub-kit change) and it's not a warrantied replacement — Mercury built those cases heavier for a reason, so we won't pretend ours is an equal swap.
• The 5.44″ gearcase (the big "fat-shaft" case on higher-horsepower Verado — 275, 300 L6, 350, including the 5.44″ Sport Master) is likewise not made by SEI. We build the smaller 4.8″ case used on 200–300 hp Verado applications. Our 4.8″ unit may physically fit a 5.44″ application, but again, only without warranty.

If your Parts Finder lookup shows a 19-spline fat shaft, a TorqueMaster/Sport Master designation, or a 5.44″ gearcase, don't order a standard unit blind — contact us first with your serial number and we'll tell you honestly whether we have a fit.

Yes, the Gen II lower unit is available on its own if your upper is sound. That's a common choice after skeg or case damage, since metal from a damaged lower normally isn't pushed up into the upper. Pull the top cap off your upper - there's just an O-ring sealing it - and inspect before deciding. Confirm your ratio with the drive serial number first.

Yes, the Gen I upper is available separately, as is the lower - plenty of customers replace only the half that's failed. Confirm your ratio first from the drive serial number or a gear tooth count, because the upper and lower have to match. Note that if your old ratio is listed as 1.84, that was replaced by our 1.81, and 1.50 by our 1.47.

No. To convert to Gen II you have to change the transom assembly as well - a Gen II drive will not go onto a Gen I transom. The flywheel and bellhousing don't change, but if the engine is already out and the coupler is original, we'd recommend replacing the drive coupler while you're in there.

Yes - our uppers and lowers interchange with the OE uppers and lowers without an issue, so you can replace just the half you need. A lot of customers buy only the lower and keep their existing MerCruiser upper. The ratio still has to match across both halves, so confirm it before ordering.

Yes - the mid-1970s inline 6 applications around 165 HP typically take our Gen I complete drive in the 1.62 old-style ratio. Send us the outdrive serial number and we'll confirm. We'd recommend the Gen I installation kit alongside it.

Yes - the 3.7L and the 470 are typically the 1.81 ratio in our Gen I range, and the inline 4-cylinder 170 HP applications land there too. We'd still want the drive serial number or a gear tooth count to confirm before shipping, since the ratio is what determines whether the boat props correctly.

Yes. We make complete Alpha One Gen I drives and lower units that fit 1972-1990 applications, in the correct ratio for your engine (for example 1.47 for a 5.7L V8, 1.94 for a 3.0L). Give us your drive serial number or engine details and we'll match the exact ratio and get you the right part.

Yes - the 3.0L applications from the mid-1980s typically take our Gen I complete drive in the 1.94 ratio. Send us the drive serial number and we'll confirm; if the number has worn off, drain the upper, pull the top cap and count the teeth on the two gears and we'll match it from that.

Yes - a V8 application like a 5.7 or a 302 is normally the 1.47 ratio in our Gen I complete drive. It's worth double-checking by counting the teeth in the upper if you can't read the drive serial. Your original shift cables will work with it as long as they're still in good condition. We'd recommend adding the Gen I installation kit rather than reusing old hardware.

Yes. The Gen II complete drives cover the 1991-and-newer Alpha applications. As a rule of thumb a 4.3L is usually the 1.81 ratio and a 5.0L usually the 1.62 - but treat that as a starting point, not a guarantee, because the ratio is the one thing we won't guess at. Send us the drive serial number (port side of the upper, on or under the MerCruiser sticker) and we'll look it up exactly. Price is the same across the ratios.

Yes. We make Gen II (1991-and-newer) complete drives and lower units, matched to your gear ratio. Confirm the ratio from your drive serial number (or count the gear teeth) and we'll point you to the correct SE116-series unit.

Our new transom assemblies are the Alpha Gen II and the Bravo. Going from a Gen I to one of the newer transom assemblies is generally not too difficult, but it starts with a solid platform - the transom and stringers have to be sound. Beyond that there are two additional holes to drill in the transom mounting, and we'd recommend using a template. The steering ram is reused or bought new, as is the trim pump. Contact us and we'll walk through what your boat needs.

No - the inner plate is only supplied as part of the complete transom assembly. Our Bravo transom replacement bolts up exactly the same as the original and comes with all new hardware, so if the plate is corroded the complete assembly is the route.

Yes - from 1968 to 1997 the V8 and the 4-cylinder use the same lower unit, as long as both are standard rotation. So a lower advertised for a V8 application will serve a 4-cylinder of that era. What does differ is the upper, where the gear ratio lives, so confirm your ratio from the drive serial number before ordering.

Yes, and you can change just the lower without replacing the whole drive. The pin on your old shaft was needed for the gears in the original lower; our lower is designed differently and doesn't need it. Send us a photo of the driveshaft splines if you want us to confirm which style you have before ordering.

That combination existed only briefly. MerCruiser paired the 330 HP 454 with the Alpha for a few short years and then stopped, rating the Alpha to 300 HP thereafter - and neither the OEM nor we warranty an Alpha above 300 HP. On that specific pairing we'd expect a 1.32 gear ratio. If you're running that much power we'd point you to a Bravo instead. Send us photos of the drive and we'll confirm what you have.

The lowers can be the same and both can be swapped for ours, but be aware of a knock-on issue: if one boat has a 5.0L upper and the other a 5.7L upper, the gear tooth counts differ between them. That means the two engines will need different throttle positions to run in sync. It's not a fault, it's a consequence of the mismatched uppers - worth knowing before you chase a synchronisation problem.

The SE106 replaces most MerCruiser sterndrives from 120 to 260 HP built 1967 to 1990 - the Alpha One Gen I era. Two conditions: your drive must have trim and tilt to use our replacement, and if it's a 1967 to 1969 you need to verify you have 13 splines on the upper driveshaft. We publish an SE106 application guide that lists the coverage in full. Send us your drive serial number and we'll confirm the exact ratio.

A 383 stroker isn't so powerful that the Alpha wouldn't hold up, and there are a lot of people running exactly that combination. We wouldn't attach our warranty to it, so that's your call to make. Bear in mind a Bravo is physically bigger and absorbs more power to turn, so you may not gain as much performance from switching as you'd expect.

Yes - our uppers match up fine with an OE lower, and equally our lowers work with an OE upper. That makes it practical to replace just the half that's failed after a rebuild or an impact. The ratio has to match across the two halves, so send us the drive serial number and we'll verify before you order.

Yes, that's possible. The decision you have to make first is what overall gear ratio you want, since that determines which upper and lower combination you need - and it's the part we can't advise on. Check with your boat builder what ratio they'd have specified for a dual-prop drive on your hull, then come back to us with that.

We wouldn't recommend it. Bravo One lower units are limited to a 16-inch prop diameter, and if you're currently on a Bravo Two your prop is larger than that - the Bravo Two is a workboat-style drive designed to swing a bigger prop and move heavier boats. If you're coming off a Bravo Two, the Bravo Three (our SE121 upper with SE128 lower) is the swap we'd point you to instead, and it's a very common one.

Usually yes, provided the ratio matches and your upper is new enough to have the oil recirculation hole. Send us the drive serial number and we'll confirm the ratio before you order, since the lower on its own doesn't tell us that. The lower doesn't include install hardware, anodes or gear lube.

For a Bravo One lower there's only one ratio, so the SE121 is correct regardless - the only thing we need to know is whether you have single (side only) or dual water intakes. Bravo Three is different: there the ratio matters enormously and we need the drive serial number or tooth counts from both halves.

Yes - we have customers running our Bravo Three behind diesel engines in the 300-plus horsepower range. As always, the part we can't help with is establishing the correct gear ratio for your particular boat and engine combination; the boat builder is the right source for that.

No. We didn't sell the XR version and we don't make a replacement for it. The Bravo lower units we make are the standard Bravo, rated at 425 HP, the same as the OEM units were. A boat running an XR is normally making well above that, so even where something bolted up it would be over our rating and would go out without warranty. If you're not certain which Bravo you've got, send us a photo or the drive serial number and we'll tell you - contact us.

We make Bravo One and Bravo Three lowers and complete drives (and Bravo Two upper units). Which one you need comes down to prop count, spline count, gear ratio, and the drive's oil system - tell us your drive serial number and we'll pin down the exact Bravo replacement. Note we do not make a Bravo Two lower unit.

A Bravo One or Three will physically bolt up, but we can't promise how it will perform - the Bravo Two swings a larger-diameter prop to move heavier boats, so switching away from it usually hurts performance, and we won't warranty a non-matching application. It's best to stay with the drive your boat was set up for; contact us to talk it through.

It's a common and workable swap physically - all the Bravo transoms accept a Bravo One, Two or Three. The hard part is the gear ratio, and we genuinely can't advise on that: your boat builder chose the Bravo Two for a reason, and the right resource is to ask them what ratio they'd have used had they built it with a Bravo Three. Be aware a Bravo Three is a smaller drive that happens to carry two props, so on a heavy hull you may gain speed and economy but shorten its life - which is why we won't warranty a non-matching application. We'll happily sell you one if you decide to go that route.

From us you'd get the transom assembly and the drive, plus the install kit. From elsewhere you'll need a propeller, an engine-mounted raw water pump - a Bravo has no pump in the drive - and a shift bracket to replace the Alpha shift bracket on the engine. There may be a few small items beyond that. Worth noting on horsepower: the Alpha was only ever rated to about 300 HP, so if you're running more than that, moving to a Bravo is the right call for longevity.

It's a substantial job. Beyond the transom assembly and drive from us, you'd need the bellhousing on the back of the engine, the shift bracket on top of the engine, and the engine coupler. We'd strongly suggest investing in a Bravo OEM shop manual before taking it on. Also check the moisture content of the transom wood core first - there's no sense mounting a new assembly to a soft transom.

Our Bravo units are rated at 425 HP, the same as the OEM units were. If you're running more than that - a big stroker build, for instance - it's over our limit, so it would go out without warranty even though it may well hold up fine in practice. For comparison, the Alpha was only ever rated to around 300 HP, which is why we steer higher-output boats toward a Bravo.

You'd change the upper and lower, the transom assembly and the engine water pump, plus all the associated hardware - it's a substantial job rather than a drive swap. A Bravo will not simply bolt onto an Alpha transom. Contact us and we'll go through exactly what your setup would need.

It's more than swapping the drive. You'd be changing the transom assembly as well, and a Bravo needs the water impeller assembly mounted on the engine rather than in the drive. It's worth doing your research and starting from a solid platform before committing. Contact us and we'll walk through what your particular boat would need.

We don't make a recommendation on replacing a complete Bravo X drive - that isn't a swap we'll advise on. If what you need is the lower unit only, that's a different question: our SE121 and SE128 lowers do work on Bravo X drives. Tell us which half you're replacing and we'll confirm the right unit.

Our Bravo replacement transom assembly will work across the Bravo era, including early-1990s boats. The differences in the inner plate come down to the motor mount hardware and the fact ours uses the newest fittings for the pitot and the gear lube bottle. It attaches and bolts up exactly the same as the original.

Our transoms are intended for pre-SmartCraft boats and come with the older 2-wire analog trim and tilt-limit sensors. They can be used with newer SmartCraft engines, but you have to swap the 2-wire analog sensors for 3-wire digital sensors - the port-side 2-wire tilt limit needs to become a 3-wire digital sensor for SmartCraft to read it. We can't supply them with SmartCraft sensors or a Mercathode, so both have to be transferred from your old transom or bought new. If you're seeing four trim wires, that's two for the trim limit switch and two for the trim sender.

For the OMC Cobra, yes - we offer a direct lower-unit replacement (SE109/SE117) or a conversion kit to switch to a MerCruiser Alpha Gen II style drive. We do not make a replacement drive for the Stringer, though we do carry some Stringer seals and gaskets. Tell us your year and engine and we'll point you to the right path - the Cobra conversion is a common fix as OMC parts get scarce.

Yes - we make a direct lower-half replacement for the OMC Cobra, which is the simpler option if your upper is sound. Two things to know: our unit uses a 1-1/4" propshaft, so you'll need the correct thrust washer for the prop, and the lower doesn't include install hardware, anodes or gear lube. It does come with the O-rings that sit between the upper and lower housing. Send us your year and engine and we'll confirm the right unit.

Yes, the shift cable comes with the conversion kit, so you don't need to order it separately. You will still want the installation kit and an anode kit alongside the conversion kit and the drive itself.

We sell the transom assembly and the drives, but a full conversion goes well beyond that - you'd potentially be changing the exhaust, flywheel cover, shift plate, possibly the intake and carburettor, and other engine-side items to match. For a whole-boat swap you may genuinely be better off sourcing a used complete package from a MerCruiser-powered boat. For a drive-only conversion, the Cobra conversion kit plus a MOD drive is the straightforward path.

We can supply the drive, the transom assembly and a complete trim pump. What we can't provide is the rest of the engine-side conversion: the bellhousing, manifolds, risers, exhaust Y-pipe and water pump housing would all need sourcing elsewhere. For a change of that scope it's worth pricing a used complete package from a MerCruiser-powered boat as an alternative.

Yes - our lower unit is a direct replacement for the OEM, so the ratio is the same. Your existing water pump in the upper unit will work with it as well, so there's nothing to change there. Tell us your year and engine and we'll confirm the right unit.

With the transom out and reglassed you have all three options open. You can run the OMC transom with our conversion kit, move to an Alpha Gen II transom, or go full Bravo. Our best practical advice is to make or obtain a drilling template for the MerCruiser and see how it lays out on your transom first - the main opening is a standard size across manufacturers, so it's the bolt pattern that decides it. Contact us and we'll talk through the trade-offs.

Both work, and it mostly comes down to budget and how long you plan to keep the boat. A direct Cobra lower replacement is the cheaper route; the full conversion to an SE116 Gen II drive - drive, conversion kit, install kit and anode kit - costs meaningfully more. The conversion moves you onto a platform with far better long-term parts availability, which is why many customers choose it as OMC parts get scarcer. A third option worth considering is simply changing the transom assembly. Contact us and we'll itemise both ways for your boat with current pricing.

Four things per engine: the complete Gen II sterndrive in your ratio, the Cobra conversion kit, an installation kit and an anode kit. On a twin-engine boat you'll need two of each, and one of the drives will be counter-rotation. Tell us your year, engine and ratio and we'll price the whole package for you - it's a common fix now that OMC parts are getting scarce.

Four items make up the job: the conversion kit, the modified Gen II drive, an installation kit and an anode kit, plus shipping. The drive has to be the "MOD" version - our SE116 Gen II sold with the conversion modification - and the 1.62 ratio was commonly used with the 5.0L engines in the MerCruiser lineup. Read the conversion kit page and the instruction PDF before committing. Contact us and we'll price your exact setup at current rates.

We publish the installation instructions for the conversion as a PDF on our site, along with a page listing all the drive gear ratio options available for the conversion. Between those two you can work out exactly what your boat needs. If you'd rather talk it through, contact us.

The conversion kit covers OMC Cobra applications up to 1993. For those years you can use your existing OMC transom assembly and convert to an Alpha One Gen II drive - you'd need the conversion kit plus a MOD-version drive. For a 1994-and-later boat, we sell Alpha Gen II replacement transom assemblies and drives, but that route leaves you a considerably longer parts list.

There is a conversion path and we can supply the instructions for going from a Lightning to a Magnum gearcase. Be aware we only warranty gearcases that are direct replacements for what the engine was originally built with, so in this case the unit would be sold without the 3-year warranty. Tell us your full engine model number and we'll confirm which gearcase yours was built with.

Yes - for example the 90-308-B covers counter-rotation applications such as the J200CXECM. As with all our J/E units, it doesn't come with the upper driveshaft, shift shaft or water pump, and it comes in black. Send us the full engine model number and we'll confirm rotation and the exact unit - the model number tells us whether it's a counter.

Yes - our SE316 is the Magnum 2 replacement, covering many of the E-TEC 200 to 300 HP applications. Note that some engines originally built with a Magnum gearcase were later updated to the Mag 2 case, so the model number is what we go by. You'll reuse your existing upper driveshaft, shift shaft and water screens; the water pump kit and anode are separate. Send us the model number and we'll confirm.

Yes, though which unit you need depends on the gearcase rather than the horsepower - a 115 can land on our SE305 (90-305-A), the SE306-C or the SE304 depending on the model. That's exactly why we ask for the full engine model number instead of year and HP. None of them include the water pump, upper driveshaft or shift rod, so plan for those alongside. Send us the model number and we'll confirm which one fits.

Yes - the V4 applications are covered by our SE304 (90-304-A), SE305 (90-305-A), or in some cases the 90-306-C, depending on the exact gearcase your engine was built with. Our units don't include the upper driveshaft, shift shaft or water pump, so most orders also take a driveshaft and a water pump kit. Send us the full engine model number and we'll tell you which one you need.

Yes - the V6 applications with the 1.83:1 ratio take our SE306 (90-306-B), which covers a wide range of 150 to 225 HP Johnson and Evinrude engines. You'd also want the upper driveshaft and a water pump kit, and a correctly sized thrust washer for your prop. Send us the full model number and we'll confirm which of the SE306 variants matches.

Yes, for many V4 and V6 applications - but the gearcase TYPE (not just HP or year) determines the right unit, so we need your full engine model number. Note the J/E lower includes the gearcase, gears, prop shaft, and lower driveshaft, but you transfer your water pump, upper driveshaft, and shift rod. Send us the model number to confirm.

We make the M2 (Magnum 2) gearcase, not the M1. Worth knowing: some engines that originally came with a Lightning or L2 gearcase were warranted by BRP with Magnum gearcases fitted in their place, so what's on the engine now may not be what it left the factory with. The main thing to confirm is the shift shaft, since the Magnum version looks different. Send us your model number and photos and we'll identify what you actually have.

There is, and which one comes down to whether your powerhead is a V4 or a V6. The 115 HP jet drives are V4s and take our 90-304-A up to 1997, or our 90-305-A from 1998 on. The 150 HP jet drives are V6s and take our 90-306-B. Bear in mind this is a conversion, not a straight swap: the engine has to be able to shift a gearcase, so the shift shaft and shift mechanism need to be there in the midsection. Contact us with your full model number and we'll confirm what your engine needs before you order.

Typically five things: the lower unit itself, the upper driveshaft, a water pump kit, a correctly sized prop thrust washer, and gear lube (we sell a kit with two quarts and a pump). You'll reuse the anode, shift shaft and mounting hardware from your old unit. On some models the existing driveshaft can be reused, which drops one item - give us the engine model number and we'll build the exact list.

We don't recommend it, and if you did it we wouldn't warranty it. They're different gearcases built for different applications, and swapping across brings prop shaft and shift system differences with it. Send us your engine serial number and we'll tell you what your motor was originally built with and what we can supply for it.

Yes - the SE207 covers the Mercury 150 HP inline 4-cylinder four-stroke at a 1.92 ratio, in 20" and 25" shafts, with the SE208 as the counter-rotation equivalent. Two things it does not cover: the Pro XS, and the Verado 150 - for a Verado 150 you want the SE221 instead. Send us the engine serial number and we'll confirm which family your motor sits in before you order.

Yes - the SE206 covers most of that range, which takes in the XR6, Black Max, Offshore and many Optimax 150 to 225 applications. It comes in 1.87 and 2.00 ratios with 20" and 25" shafts. The serial number usually confirms the shaft length but often not the ratio, so plan on a spin test or tooth count before ordering.

Yes - those applications typically take our SE216 in 1.75 ratio, in either 20" or 25" shaft depending on your motor. Send us the engine serial number and we'll confirm the shaft length and the exact unit. These move quickly, so it's worth asking about current stock and lead time at the same time.

Yes - the SE216 covers many of the 3.0L applications at a 1.75 ratio, in 20" and 25" shafts. Two things to confirm: your shaft length, and whether your driveshaft is 8-spline or 13-spline, since both exist in this range. An 8-spline motor needs its upper driveshaft sourced from Mercury, so find that before ordering. Send us the engine serial number and we'll work it through with you.

Yes - the SE221 is what we call the "Verado style" gearcase, covering the Verado inline 4 and 6-cylinder engines and some 3.0L V6 DFI applications. Important detail: around 2006, at engine serial number 1B504989, the 3.0L V6 engines changed from our SE216 to the SE221, so the serial rather than the model year decides it. The SE221 has a 15-spline prop shaft. Send us your serial and we'll place you on the right side of that change.

Yes - that range is covered by our SE205 family. Two things decide which one: the gear ratio (2.07 or 2.33) and whether your motor has a 3-jaw or 6-jaw reverse clutch. If yours is the older 3-jaw, our unit will still work but you must also fit the mid-section shift shaft kit and pull the powerhead to change it. Send us the engine serial number and we'll tell you the ratio and which clutch system you're on.

We make lower units across much of the Mercury/Mariner line, but fitment is by serial number - the same HP and year can need a different unit depending on shaft length, rotation, shift system, and gearcase type. Send us your serial number and we'll tell you exactly which unit fits (or if it's one we don't cover).

Yes - they're separate part numbers rather than an option on the standard unit. The SE218 is the counter-rotation partner to the SE216 (1.75 ratio, 25"), and the SE228 is the counter-rotation Verado unit covering 1.85 and 2.08 ratios in 25" and 30". On a twin installation send us both engine serial numbers and we'll pair the standard and counter units correctly.

Our jet drive range is focused on specific applications - we make the SEI jet drive lower for certain Tohatsu models, and for some other jet setups we may have an impeller and liner but not a complete unit. Tell us the engine and year and we'll tell you exactly what's available rather than leaving you guessing.

No - we make the 4.8-inch gearcase, not the 5.44. The 5.44 is the larger, upgraded case found on higher-performance boats, and all the 5.44 Sport Master gearcases are the same. The 4.8 we make was used on the 200-300 HP models. If your engine originally called for a 5.44, our 4.8 is not a direct replacement: it would go out without warranty, and that stays true even if someone has already fitted a 4.8 to it, because what matters is what the engine was built with. 350 Verados normally came with the 5.44. Send us the outboard serial number and we'll confirm which one you have before you order.

Not as a kit - you'd have to buy everything separately, and the gear set alone is a substantial part of the cost of a complete unit. More importantly, rebuilding means giving up the 3-year fault-free warranty that comes with a complete new unit. For most customers a complete unit works out better on both cost and cover. We do sell seal kits and water pump kits for maintenance work.

Our shift shafts only work on 2006-and-older units - on anything newer the length isn't correct and you'd be best going OEM for that part. Send us your engine serial number before ordering driveshafts or shift shafts and we'll check what actually fits, since these are easy to get wrong when converting between shaft lengths.

No - our product listing states the SE216 does not replace the Torque Master, Torque Master 2 or the Sport Master, and fitting one to an engine that came with a Torque Master isn't a direct replacement, so it goes out without warranty. This catches people out because the cases can look similar once swapped. Send us your engine serial number before ordering and we'll tell you which gearcase your motor was actually built with.

Around 2006, at engine serial number 1B504989, the 3.0L V6 two-stroke engines changed from using our SE216 to our SE221 - the SE221 is what we refer to as the "Verado style" gearcase, and it covers three different engine types including the 13-spline driveshaft 3.0L V6. Because the changeover is by serial rather than by model year, send us the engine serial number and we'll tell you which side of it you're on.

The gearcase housing is the same, but the shifting system isn't - Mercury changed it around the 2004 to 2006 era. Our SE205 is built for the older shift system, so on a later motor the shift shaft protrudes a different amount and the unit won't work even though it looks identical. Send us the engine serial number and we'll tell you which side of that change your motor falls on before you order.

We make lower units for the Suzuki DF200, DF225, and DF250 (V6 four-stroke) in the standard-type gearcase, standard and counter rotation, 25" and 30" shafts. We don't cover the 20" versions, the S/SS or A gearcase types, or anything smaller than a DF200. Send your full model number and we'll confirm.

We cover the Suzuki V6 four-stroke applications - send us the full model number and serial and we'll confirm. As an example, a DF250TXXW3 takes our SE521 in the 30" standard-rotation configuration. Model coverage has expanded over time, so it's always worth asking with your exact model number rather than assuming.

Our Suzuki coverage is the V6 four-stroke engines - the DF200, DF225 and DF250 family, handled by our SE521 in standard and counter rotation with 25" and 30" shafts. We don't currently cover the smaller or older Suzuki engines. Send us your full model number and serial and we'll confirm, since coverage does expand over time.

Yes - our drives are used successfully behind 300 to 400 HP diesel engines including Yanmar, Steyr and Volvo. The one thing we can't help with is establishing the correct gear ratio for your engine and hull, and that matters: once a unit is mounted or filled with gear lube it can't be returned. Get the ratio confirmed by your boat or engine builder first.

Not easily. You'd need to buy the transom assembly and drive from us, plus all the MerCruiser accessories that bolt to the engine - it's an engine-side conversion as much as a drive swap. It's doable, but budget for a long parts list beyond what we can supply. Contact us and we'll tell you what we can cover.

Not at this time - Volvo lower units aren't something we currently produce, though we do carry some Volvo-related parts and trim components. Our product range does expand, so it's worth asking with your specific model rather than assuming the answer is still the same.

Sometimes - it depends on the exact model and year, and there are two things to check first. Your engine must have a shift shaft and a shift slide mechanism in the midsection, because a gearcase has to be shifted and a jet pump doesn't; without them there is nothing to operate the gears. You also need to confirm the shaft length you actually need, as these conversions use a 20-inch unit. Where it works, the gearcase follows the horsepower: 90 HP uses our 90-404, 115 HP uses our 90-405, and 150 HP uses our 90-416, in the A20 or B20F version depending on the year. Two we cannot do: the F90JB and the F115JB will not convert, because the driveshaft splines are different. Send us your full model number and we'll tell you which case you're in before you buy anything.

The only ratio we'll sell with a warranty attached is your direct replacement - the one your engine was built with. We identify that from your full engine model number rather than from year and horsepower. Send us the complete model number and we'll confirm which unit is the direct match.

Yes, our standard lower will replace it, but you'll need to buy a new propeller and prop hardware to suit - the dual-prop setup uses different hardware entirely. Send us the model number and we'll confirm the correct single-prop unit.

Our replacement lower unit can take an outboard from 20" to 25" on some models. What we don't supply is the remaining hardware - a midsection extension or any associated fittings would have to come from elsewhere. Tell us your engine model number and we'll confirm whether the lower alone gets you there.

Yes - the LF prefix indicates counter rotation, and those applications are covered by our 90-428 family. Make sure you're running a left-hand propeller with it. If you're on a twin installation, the starboard side will take the standard rotation equivalent instead - send us both model numbers and we'll pair them.

Yes - the 90-428 family covers those counter-rotation applications. If you're running a single engine with a counter-rotation unit, please verify you have a left-hand prop before ordering, and note we'd generally advise moving a single-engine boat back to standard rotation. Send us your full model number and we'll confirm.

Yes - we make a jet drive lower for the Yamaha 50-60 HP four-stroke applications from 2002 up with the 16-tooth driveshaft. Fitment is by shaft length, so a 20" model is what most of these take. Important: if the boat currently runs a propeller motor, you'd need to raise the motor almost 7 inches for the jet to work properly, so it's not a bolt-on swap.

Yes - the 90-405 family covers the Yamaha 115 applications, including the V4 2-strokes and the F115 four-stroke, in 20" and 25" shafts. It comes complete with the water pump installed; you bolt it on, add gear lube and fit your prop. Send us the full model number - for example F115TXR or C115TLRX - and we'll confirm the exact unit.

Yes - the 90-416 family is our main coverage there, spanning the 2.6L V6 2-strokes (OX66, HPDI, V-Max, Z200 and similar) and the 150-200 4-strokes, in 20" and 25" shafts with counter-rotation available as the 90-418. Put your full model number into the search bar and confirm it appears under the technical tab on the product page.

Yes - the 90-421 family covers the OX66, VX, SX and Z-series 225 and 250 applications in 20" and 25" shafts. These are complete units: bolt on, add gear lube and fit the prop. Send us the full model number (such as Z250TXRC or S225TXRV) and we'll confirm which variant applies.

Yes - the 90-404 family covers the Yamaha 75 and 90 HP applications, including the older 2-strokes and the F90 four-stroke, in the 20" shaft. These do go on backorder periodically, so it's worth asking for the current ETA. Our units come with the water pump installed; you'll fill it with gear lube and transfer or replace the anodes, prop and prop hardware. Send us your full model number to confirm.

Yes - the F150 applications are covered by our 90-416 family. An F150TLRD takes the 20" version and an F150TXRD the 25", so the letters in your model number determine it. Put your full model number into the search bar on our site and check it appears in the application guide on the product page.

Yes - the F225 applications such as the F225TXR and F225TXRC are covered by our 90-421 family. It comes as pictured in black, ships without gear lube, and doesn't include the anode or install kit. You reuse your mounting hardware, anodes, prop and thrust washers. Send us your full model number and we'll confirm.

Yes - the F250 applications are covered by our 90-422 family in standard rotation and 90-429 in counter rotation, with 25" and 30" shaft options. Send us the full model number (for example F250TXR or LF250TUR) and we'll confirm the exact unit, since the shaft length is carried in that model number. The 30" units ship in an oversized box, so factor in higher shipping.

Yes - the F300 XCA applications are covered by our SE423 family. These are a newer gearcase for us and do go in and out of stock, so it's worth checking the current lead time when you enquire. Send us the full model number and we'll confirm the exact unit and current availability.

Yes - the SE423 family covers the F300XCA and a number of the newer four-stroke applications, including some from 2020 onwards. Note the year selector on our website may not extend that far yet, so don't take that as a no: search by model number or contact us and we'll check directly. These are newer to our range and move in and out of stock.

Yes - the F300UCA and LF300UCA applications are covered by the SE423 family, with separate part numbers for the standard and counter-rotation sides. They come in black only; you can repaint them without affecting the warranty. Send us both model numbers if you have twins and we'll pair them correctly.

Yes - the F75 and F90 four-stroke applications are covered by our SE404 family. Send us the full engine model number (something like F75TLRD) and we'll confirm the exact unit and shaft length. These do go on backorder from time to time, so it's worth checking current lead time when you enquire.

Yes - the OX66 and HPDI applications in that range are typically covered by our SE416 family, in standard rotation (90-416) and counter rotation (90-418). Confirm by putting your full model number in the search bar and checking it appears in the application guide on the product page. If you have a counter-rotation model, make sure you're running a left-hand prop.

We make lower units for many Yamaha outboards from 75 HP up, but we match on the full engine model number (like F150TXR), not just year and HP - the model number carries the stroke type, shaft length, and variant we need. Send us the full model number and we'll confirm the right unit or let you know if it's outside our coverage.

Alongside the lower unit, plan on lowering the motor on the transom. Typically a 25" transom boat runs a 20" jet drive, so switching to a propeller means going to a 25" setup and dropping the engine down accordingly. Tell us the engine model and your transom height and we'll confirm which lower unit applies.

Measure the round part of the gearcase (the bullet, near the prop) outside-to-outside. 4-1/4 inches = Big Foot; smaller than that = standard. On the 40-60 HP motors, SEI's lower unit is the Big Foot version.

Measure the round part of the gearcase - the bullet, up near the prop - outside to outside. 4-1/4 inches means it's a Big Foot; anything smaller than that is a standard foot. If you'd rather not guess, send us a photo of the lower unit and we'll identify it for you. Big Foot gearcases are most often found on pontoons and heavier vessels rather than lighter runabouts.

This is the check that applies to the SE206 family. Measure the bullet - the round part of the gearcase by the prop - outside to outside: 4.25 inches is the small case and 4.75 inches is the large case. It matters because it rules ratios in and out. Send us the measurement along with your engine serial number and we'll tell you which unit applies to your motor.

That measurement separates the small case from the large case (4.75 inches), and it's the check that matters on the SE206 family and on the SE304 and SE306 units. Which way it points you depends on what your engine was built with, so send us the figure along with your engine serial or model number and we'll confirm the right unit - and tell you whether a prop change comes with it.

It tells you which gearcase family you have, and it rules ratios in or out. On the Mercury outboards, the 1.78 ratio exists only in the small case, which measures 4.25 inches across the bullet outside to outside - if yours measures 4.75 inches you have the large case and it can't be a 1.78. Measure before ordering, because forum advice about "all of them being the same" frequently isn't right.

It depends on your engine model, and we publish a chart showing it - a "No" in the "must purchase upper driveshaft" column means your existing shaft is interchangeable with our unit. In that case you remove it from your old gearcase and install it into ours by lining up the splines and tapping it in with a rubber mallet. Send us your model number and we'll check the chart for you.

The engine model number tells us, so send that over. On the two-piece applications you can reuse your existing driveshaft in our new unit. Be careful comparing measurements - a driveshaft measuring 27.25 inches from the top of the splines down to the edge of the case corresponds to what we call a 25" driveshaft, so a longer measurement than the label doesn't mean it's the wrong part.

Yes, the driveshaft will work in ours, but you need to remove the clips from your old shaft first. There's a note about the driveshaft clips on the application tab of the relevant product page. Our gearcase already has a new retaining clip pre-installed waiting for the shaft to drop into it.

On the two-piece applications you reuse the top part of your existing shaft, so there's nothing extra to buy. Our stub shaft units (the "S" in a part number such as 90-218-AS) are the versions made for two-piece driveshafts. Tell us your serial number and we'll confirm which configuration your motor uses.

Yes. You'd fit a counter-rotation drive or gearcase, change to a left-hand propeller, and reverse the shift cable at the helm control on that side so it throws reverse correctly. Alternatively you can leave the setup exactly as it is and simply order another standard rotation unit - nothing else then needs to change.

It can be done, but only if you change to a right-hand propeller and check the shift linkage at the same time. Be aware this is serious: if you run a standard as a counter - or a counter as a standard - without changing the prop and, on a digital throttle boat, reprogramming the throttle, the gearcase will destroy itself. We see the specific damage that causes, so please don't skip either step.

Yes - that's one of the nice things about the Bravo. What dictates the rotation is which way the shift cable moves, combined with running the correct propeller for the direction you want. So if you have one left-hand and one right-hand prop on a twin setup, you already have one side running counter.

On a single-engine boat you want standard rotation with a right-hand prop. On twins, the starboard engine is standard and the port engine is normally counter-rotation with a left-hand prop, which cancels out torque steer. The quickest check is simply which prop is fitted - send us a photo of the prop and the back of the boat and we'll confirm. On older twins it wasn't unusual to find two standard drives rather than a standard/counter pair, so it's worth verifying rather than assuming.

You can't tell by shifting it on the bench - a standard and a counter will both feel the same there. Take the prop off and look down into the exhaust cavity at the prop shaft bearing carrier, where you'll see a visible difference between the two. We also have a counter-rotation identification guide we can send you.

We'd advise switching back to a standard rotation unit with a right-hand propeller if that's an option for you. We're not big fans of single-engine counter-rotation setups: counter-rotation lower units aren't built quite the same way and frankly aren't quite as strong as the standard rotation units. On a single-engine boat there's no torque-steer reason to run one.

No - Yamaha changes direction in the lower unit, not the powerhead. Both engines' flywheels spin the same way when running and both shift the same direction; what differs is which way the prop shaft turns inside the lower unit. That's why a rotation change on a Yamaha is a lower unit change.

No, and this one trips a lot of people up. All the MerCruiser sterndrive engines were left-hand rotation, exactly as they were in automotive applications - that refers to the engine, not the drive. A single-engine boat is standard rotation with a right-hand prop. Right-hand rotation engines do still exist in the field but they're rare and were generally inboard boats.

A single-engine boat uses standard rotation (right-hand prop). On twin engines, one runs standard and the other counter-rotation (left-hand prop) so the boat tracks straight. Counter-rotation uses a different lower unit - confirm your rotation before ordering, and on a twin setup make sure you're matching the correct side.

They're separate part numbers rather than a configurable option - for the 1.75 ratio 25" application, for example, the SE216 is standard rotation and the SE218 is the counter-rotation unit. Send us your engine serial number and we'll give you the exact standard or counter part number for your motor.

Usually yes - an "L" in the model number indicates a 20" driveshaft and an "X" or "XL" indicates 25". That holds as long as nothing has been changed on your motor, and conversions between lengths do happen. It costs nothing to confirm by measuring, so we'd recommend doing both before ordering.

Measure from the top of the driveshaft down to the gearcase mounting surface - the flat part that meets the midsection, past the water pump. About 23 inches means a 20" shaft, about 27 inches means a 25", and about 33 inches means a 30". Measuring from the cavitation plate instead will give you a different number and is the most common reason people order the wrong length.

Measure from the top of the driveshaft down to the mating surface past the water pump. About 22.5 inches corresponds to a 20" shaft. If the number you get sits between sizes, send us the measurement along with your engine serial number and we'll tell you whether you need the 20", 25" or 30" unit.

Measure it, because either could be correct. Motors do get converted between shaft lengths, and once that's happened the model number no longer reflects what's fitted. Measure from the top of the driveshaft to the gearcase mounting surface past the water pump: around 23 inches is a 20", 27 inches is a 25" and 33 inches is a 30". Send us the figure and we'll match it.

Measure from the top of the lower unit case to the top of the shaft: 22 to 23 inches is a 20" unit, 27 to 28 inches is a 25", and 32 to 33 inches is a 30". The letter in your model number is a good cross-check - L indicates 20" and XL indicates 25" - but if the motor has been converted between lengths, only the measurement is reliable.

No - the splines are the same from 1972 through 1990, so there's no concern there when fitting an Alpha One replacement across that range. Spline count is worth checking on the Mercury outboards, where 8 versus 13 does matter, but not on the Alpha drives in that period.

Those are the only two options, and you'll need to drop the current lower unit and count the splines on the end of the driveshaft that goes into the engine. Year is a reasonable guide - later motors are 13-spline - but it should be confirmed. If you find 8 splines you'll need to source that upper driveshaft from Mercury, and we'd strongly recommend locating it before ordering the lower unit.

No. Splines on the driveshaft or prop shaft have nothing to do with the gear ratio - that's a common mix-up. The ratio is set by the gears inside the unit, so you need a tooth count on the pinion and forward gear, or a spin test. Spline count matters for fitment, just not for ratio.

It takes the same hub kit as your original drive, so if the prop was working on the old unit the same hub kit carries over. Source it from whoever made your propeller, or from a Mercury dealer on the MerCruiser applications - we don't hold those hub kit part numbers. The exception is where you're changing case type, which can change the prop shaft and therefore the hub. Tell us the unit and the prop you're running and we'll tell you whether it carries over.

No - and this is the mistake we see most often on Bravo orders. There are only three SEI uppers and each is used at several different ratios: the 30/23 upper, for instance, appears on a 1.65, a 2.20 and a 2.43 drive. The ratio comes from the upper and lower gear sets together, so you need the tooth count from both halves, or the drive serial number. Getting it wrong is expensive - once the drive is bolted up it cannot be returned. Contact us with the serial and we will confirm it.

Yes - all the Bravo transoms will accept a Bravo One, Two or Three. That's why going from a Bravo Two to a Bravo Three is a common swap physically. The thing that isn't interchangeable is the gear ratio and propping, which is where you need to be careful.

No - Bravo One lowers are built in a single ratio, unlike Bravo Three lowers which come with different gearing options. The only choice to make on a Bravo One lower is the water intake configuration: 90-121-02 is side intakes only, and 90-122-02 is side plus low water intakes.

Strip and count both sets: the driveshaft housing assembly gear set at 30/23 and the gear housing assembly gear set at 16/27 together confirm a 2.20:1. Bravo Three ratios are determined by both the upper and the lower, which is why we ask for the drive serial number or counts from both halves. We see a lot of mistakes on Bravo Three replacements where the ratio isn't right, and once bolted up they can't be returned.

Count the teeth on the gears in BOTH halves - the ratio comes from the pair, so neither half tells you on its own. Then find your combination in this chart. Note that the Bravo Two has no SEI lower unit; we make the upper only.

If your counts do not land on a row here, recount before ordering - once a drive is bolted up it cannot be returned. You can also just send us the drive serial number and we will look the ratio up for you.

Dual water intakes have pickups on the leading edge of the gearcase in addition to the side intakes. If all you have are the side intakes, that's the single. It's the one thing we need to know when ordering a single-prop Bravo One lower - and usefully, the single and dual versions interchange without fitment issues.

A dual water pickup has additional pickups on the leading edge of the gearcase. If all you have is the holes on both sides that the ear muffs cover, that's a single pickup. Usefully, the single and dual Bravo One lowers can be interchanged without any fitment issue, so it isn't a decision you can get badly wrong.

That hole benefits cooling on the upper through oil circulation. The old modification of drilling and plugging to match is something we no longer support under warranty. If your upper doesn't have the mating hole, the modification is acceptable if needed - but we'd never suggest going the other way and plugging an upper, because the upper benefits significantly from that additional cooling. The newer Bravo Three lowers have the oil recirculation hole as standard.

The bump rings are the brass rings in the upper unit that the clutch fork "bumps" against to bring a Bravo out of gear. It's not unusual for the clearance to be tight on a new unit, which is part of why a new Bravo can feel firm shifting until it's broken in.

The lower unit is the same for both - it's the upper that changes. For the 2.20 ratio you need the 90-121-01A upper rather than the 90-121-01B used for the 2.00. Spline counts are identical across them, so there's nothing else to worry about there. The ratio doesn't change the price either.

The SE121 is the Bravo upper unit and the SE128 is the Bravo Three lower. All Bravo uppers are the same apart from gear ratio (and the older-style MerCruiser gearcase from the 1990s), so it's normal to see SE121 stamped on the upper of a boat running a Bravo Three lower. Our SE121 uppers are the aftermarket replacement for Mercury's current version, the one referred to as "swept back".

There are separate numbers and mixing them up is the most common problem we see. On an SEI unit, the serial is on a red tag inside the upper and the lower, and the same number is stamped into the case - our team can look that number up and tell you exactly what the unit is. On a MerCruiser drive, the drive serial is on the drive itself; the number on the transom bracket is the transom assembly serial, which is a different number and won't give us your gear ratio. If you're not sure which you're looking at, send us a photo.

We don't advise on ratio selection - what we do is confirm the ratio you already have so the replacement matches. Boat builders choose the gear ratio and prop together based on the hull, so if you're changing drive types the builder (or Mercury Marine for Brunswick boats) is the right place to ask. Send us your drive serial number and we'll confirm your current ratio exactly.

That case was built with two different prop shaft designs, a 1-3/16" and a 1-1/4" outside diameter, and the seals differ between them. Measure your shaft before ordering. We sell the inner and outer prop shaft seals individually as well as a complete seal kit for the whole lower unit, which is usually the better value if you're in there anyway.

They're two different gearcase sizes OMC used. The 800 series is the 4.750-inch diameter gearcase. The most reliable check is to measure your gearcase, but as a rule if you have a V6 or V8 engine it should be the 800 series. Parts listed as "800 series only" won't fit the smaller case, so measure before ordering.

That's normal. A small amount of side-to-side movement at the motor spline end and the impeller end is expected and isn't a sign of a worn unit. If you're hearing a noise you're unhappy with, the meaningful test is to run it in the water under load and then reassess.

Almost certainly not. A new gearcase with new bearings has noticeably higher rolling torque than the worn unit you took off - that resistance is normal and eases as it beds in. Measure it with the water pump off, because the impeller makes any shaft hard to turn and misleads people constantly. Rolling torque specs differ between units, so rather than work to a general figure, contact us with your unit and we'll give you the spec that applies to yours.

On our gear set listings, a dimension such as 3.26 is the outside diameter of the bearing race, not the width of the forward gear. If you're matching a gear set to an existing gearcase, measure the bearing race outside diameter to compare. Send us the gearcase model and we'll confirm which set fits.

No. The SE306 is a different gearcase from the Magnum and Magnum 2 - our unit for those is the SE316. They look similar enough in photos that they're easy to confuse. Send us the full engine model number and we'll confirm which gearcase you actually have before you order.

The giveaway is the prop shaft. The Torque Master, Torque Master 2 and Sport Master all use the "Fat Shaft" prop shaft with 19 splines, whereas our SE221 has a 15-spline prop shaft. Those three gearcases are ones we don't replace. If you fit one of ours to an engine originally built with a Torque Master it would be sold without warranty, and you'd need a prop hub change to suit the smaller shaft. Send us the engine serial number and we'll tell you which gearcase it left the factory with.

The number is the diameter of the torpedo - the bullet-shaped housing the prop shaft comes out of - so the two are 4.8 inches and 5.44 inches across. It's the first thing we ask, because we make the 4.8 and we don't make the 5.44. If you'd rather not measure it, send us the outboard serial number or a clear photo of the gearcase and we'll identify it for you. Worth doing before you order rather than after: fitting a 4.8 to an engine that called for a 5.44 means no warranty.

No - if you have SEI lower units, they are not Torque Masters. That matters when you're sourcing gears or parts, because the Torque Master is a different gearcase with different internals. Note also that our forward gear is not dimensionally identical to the Mercury OEM forward gear, so OEM gears aren't a drop-in for our unit.

Measure the base - the newer style is around 60mm and the older style is slightly smaller at around 58mm. The undersides of the two are also different, so if you still have your original base, comparing them side by side is the most reliable check. Send us your measurement and we'll confirm which one to send.

Look into the lower unit where the base sat: you'll still see some black plastic and a seal left behind. That has to come out of the lower unit before the new base will seat properly. The replacement base we supply comes with new seals for that area, so you don't need to source those separately.

Check before ordering - the O-ring and gasket in the complete kit are for the newer Alpha. If your lower is the original older unit you'll need the older-style base instead, which has the correct O-ring and gasket for it. Measure the base (roughly 58mm for the older style versus 60mm for the newer) or send us a photo and we'll confirm which you need.

Not necessarily - we identify Yamaha lower units by engine model number rather than by OEM part number. Put your model number into the search bar at the top of the page and it will take you to the correct unit if we make one. Then check the technical tab on that product page and confirm your model number and year are both listed. If it doesn't come up, contact us with the model number and we'll check directly.

We work from the full engine model number - something like F250TXR or LF150TXR - not just the year and horsepower. That model number carries the stroke type, shaft length and rotation we need to match the unit. If your ID tag is gone, send us a photo of the bearing carrier behind the prop and tell us the shaft length, and we'll work from that.

Almost certainly not. Yamaha issues a new part number for even a slight colour change, and numbers supersede frequently, so a chain of different numbers can all describe the same gearcase. What actually matters for fitment is the shaft splines, the shaft length, the gear ratio and - on some models - whether it has the water-cooled bearing carrier. We match on your engine model number rather than the OEM gearcase number, and we've sold thousands of these against it.

No. They're made in standard rotation, counter-rotation and high-altitude (HA) versions. The HA lower is only used with a 4-cylinder engine in the 2.0 and 2.4 ratios and is a standard-rotation-only drive. A single-engine boat at 1.62 would be running the standard lower. Give us your drive serial number and we'll tell you which of the three you have.

We strongly recommend staying with the ratio your boat was manufactured with. It keeps the boat performing the way the builder intended and avoids a propping problem you may not be able to solve - fitting a high-altitude gear set in the lower, for example, takes a 1.94 setup out to 2.40. Anything custom along these lines isn't backed by us and carries no warranty.

Yes, and it's the best fallback when the serial is unreadable. Drain the unit, remove the top cap on the upper and count the teeth on the two gears inside. A 22/20 count is the 1.47 ratio and 17/19 is the 1.81. Send us your counts and we'll confirm which unit you need before you order.

It takes more than the gear set - the roller bearing is different between the 1.47 and the 1.81, so you'd need that too. Beyond the parts, it has to be shimmed properly and the rolling torque set correctly, which is precision work. In most cases buying the drive in the ratio you need is the more sensible route, and a custom build wouldn't carry a warranty.

We don't offer custom configurations. Anything custom isn't something we can back, and it wouldn't carry a warranty. We match new units to old units like for like so that no disassembly or modification is required on your end.

Both halves have gears, so the ratio comes from the pair working together - which is why you can't read it off one half. The short answer: don't try to work it out yourself. Send us the drive serial number and we'll tell you the ratio outright. If you want the mechanism: the number on the tag is the combined ratio, and some upper gear sets are one-to-one, so a tag reading something like 1.62/1.65 isn't a contradiction - it's the upper and the combined figure side by side.

With the unit in forward gear, mark both shafts and count how many turns of the driveshaft it takes to get one full turn of the prop shaft. That number is the ratio: a 1.87 is 1.87 turns of the driveshaft to one turn of the prop shaft, and a 2.00 is two turns to one. Take the impeller out first so the shaft turns freely. It only works if the unit still rotates in gear - if it's locked up you'll need a tooth count instead.

If the unit is locked up a spin test won't work, so the remaining option is a tooth count. Disassemble the prop shaft side and count the teeth on the pinion gear and the drive gear - that gives us an exact ratio to match against. Send us the counts and we'll confirm the correct unit for your engine.

The most reliable way is the drive serial number - send it to us and we'll look it up and tell you exactly what ratio it was built with. You'll find it on the engine ID tag on top of the engine, or on the port side of the drive on the MerCruiser sticker. Don't go by engine size or what usually came on that boat; the serial is what we ship against.

The most reliable way is your serial number - the drive (or engine) serial decodes to the exact ratio it was built with. Don't go by engine size or "what usually came on the boat." If you can't read the serial, count the teeth on the upper and lower gears, or contact us and we'll help confirm it.

Yes. SEI's 1.62 replaces the older 1.65 - they're the same application. The same is true for other close pairs (for example a 1.94 replaces a 1.98). When in doubt, confirm with your serial number.

On a complete drive, yes - our 1.47 replaces the older 1.50 and our 2.0 replaces the 1.98. Be careful if you're buying only one half, though: the 1.98 and 2.0 half units are completely different from one another, so that substitution only holds when the whole drive is being replaced. Tell us whether you need a complete drive, an upper or a lower, send your drive serial number, and we'll confirm the exact match.

Outboards usually don't have the ratio marked on the unit, so it comes down to either a spin test or a tooth count inside the gearcase. Start by sending us the engine serial number - in many cases we can look up what it was built with. If the serial won't resolve, do the spin test with the impeller removed and count driveshaft turns per prop shaft turn.

No, not unless you're operating above about 6,000 feet of elevation. That's the high-altitude gear set. Likewise the 90-116-02H lower only fits the 2.00 and 2.4 ratio units, whereas the standard 90-116-02 covers the rest. Tell us your engine and where you boat and we'll point you to the right one.

Every MerCruiser 3.0L from the 1970s through 1997 is a 1.94 ratio - the older 1.98 designation was replaced by our 1.94. From 1998 the 3.0L moved to the 2.00 lower paired with the 1.65 upper. Send us the drive serial number and we'll confirm which side of that change your drive falls on.

Just two: 1.75 and 1.62. The 1.62 is very rarely requested - we sell only a couple a year - so in almost every case the 1.75 is the one you want. Send us your engine serial number and we'll confirm which applies to your motor.

Two things change, and both cost money. You'll need to re-prop the boat, because the old propeller will no longer be right, and depending on the unit you may need different prop hardware with it. Beyond that, a gearcase that isn't the one your engine was built with is generally sold without our warranty. Unless you have a specific reason to change, stay with the ratio your boat was built with - and if you're unsure what that is, send us the serial number.

The stock ratio for the 4.3L is 1.84. We'd still want to confirm against your drive before shipping, and we'll also need to know whether it's a single or twin engine boat so we get the rotation right.

Yes. Props from the Gen I and Gen II use the same hub kit and are interchangeable, and they also interchange with a lot of the Mercury outboard units. So if you're finding Gen I props hard to source, that's not a reason on its own to change drive generations.

Alpha One Gen I runs roughly 1972-1990; Gen II is 1991 and newer. A quick tell is the water-pump housing: plastic = Gen I, metal = Gen II. If your year is right at the 1990-91 transition, send a photo and we'll confirm before you order.

1991 was the start of Gen II, so 1990 and earlier is Gen I. Another quick tell is the gear lube reservoir in the engine compartment, which indicates a Gen II setup. We always ask rather than assume, because a drive can have been changed at some point in its life - send us the drive serial number and we'll confirm it outright.

Probably not. The Alpha Ones used both small and large bearings on the top caps; after 1995 it was all small bearing, and the small one is what we use. Any new top cap kit from us or from the OEM will come with the smaller bearing. The new smaller bearing is used with the new top cap, pressed onto your original stub shaft and then shimmed properly.

Possibly not. There's an earlier design often called the "R" style gearcase, also known as an MC-1, which predates the Alpha Gen I and is sometimes loosely called a pre-Alpha drive. The internal parts are different even though some water pump components carry over. Send us a photo of the driveshaft splines sticking out of the lower - if there's a preload pin, you're on the older style and it takes a different water pump base.

On an Alpha Gen II, yes - the Gen II upper driveshaft is hollow. The Gen I is not. If you have a Gen I with a hollow-looking shaft, it's possible someone rebuilt it using the wrong seal at the bottom of the upper unit and plugged the shaft to work around it.

It's the gear ratio. HA stands for high altitude gear set - the HA lower is used to make the 2.00 and 2.40 ratios and is fitted to the 3.0L 4-cylinder engines from 1998 onward. The standard SE116 lower covers the 1.47, 1.62, 1.81 and 1.94 ratios. Tell us your engine and we'll tell you which of the two you're on.

Yes - any Mercury number can be entered into our website search and if we make it, it will show. For a bigger job, make a list of the OEM part numbers you need and either enter them on the site or send us the list and we'll cross-reference them for you. That's usually faster than trying to identify parts from a diagram.

The number decodes the unit for you: 90-216 is the SE216 family, and the suffix gives the ratio and shaft length - A20 being the 20-inch shaft. On that particular unit you're looking at a 13-spline driveshaft, 1.75 ratio, for the 3.0L application. If you have the number off the box you can confirm your shaft length from it without measuring.

The letters decode separately - "A" is the gear ratio and "S" means stub shaft. A stub shaft unit is the version used with two-piece driveshafts. If you're not sure whether you have a one-piece or two-piece driveshaft, drop the lower and tell us what you find and we'll confirm which version you need.

Often yes - remove the trim tab anode above the propeller and the 6-digit number is stamped into the recessed area underneath it. Getting to the red tag itself does require dropping the unit, but for most purposes that stamped number is all we need. Send it to us and we can look up the build date, ratio and warranty status.

Yes - send us the 6-digit number and we can tell you the exact model, ratio and shaft length it was built as, plus when it was sold and whether it's still in warranty. That's often the fastest route when the engine's own ID tag is gone: several customers come to us having bought a boat with one of our units already fitted and no other information.

Yes - give us the serial off an SEI unit and our team can look it up and tell you exactly what it is, including the ratio it was built with and when it was sold. Contact us with the number. If the unit on your boat isn't one of ours, we'd need the MerCruiser drive serial number instead, or a tooth count from the two gears in the upper under the top cap.

Try the freeze plugs on the powerhead, which often carry the number when the ID tag has been lost or painted over. Failing that, tell us the gear ratio, engine size in litres and driveshaft length and we can usually narrow it down. Photos of the gearcase and the bearing carrier behind the prop help too.

Some older serials come back only as "MERCRUISER ALPHA" without giving the ratio or generation, and some stickers are simply unreadable. Two fallbacks: the number is also stamped into the gearcase in the same area as the sticker, and a wire wheel will often bring it up. Failing that, pull the top cap off the upper and count the teeth on the two gears - that gives us the ratio directly.

Not necessarily. A number in the style of 1623-9413-C-S is a MerCruiser casting number, which means you're looking at a MerCruiser unit rather than one of ours. An SEI unit is identified by the serial on the red tags between the two halves of the drive. Send us a photo if you're not sure what you're looking at.

They're different numbers and only the drive serial tells us your gear ratio - this is easily the most common mix-up we see. The transom assembly carries its own serial, so if the number you found is on the transom, we'll need you to go back and find the one on the drive itself, near where it says MerCruiser or Alpha. If the drive is already split into two halves, there are serial tags visible inside the cavities of both housings.

On a Mercury/Mariner outboard it's on a decal on the engine bracket that bolts to the transom, usually on the port side. On a MerCruiser sterndrive it's on the drive itself. On an SEI drive the serial is on red tags between the two halves - the drive has to be separated to see them. Send us a photo if you're not sure and we'll point it out.

It's on the inside transom plate, on a red tag carrying our logo. That's what we need to check warranty status on a transom assembly, so it's worth locating before you contact us.

Look on the port side of the upper unit, on the MerCruiser sticker or underneath it. It's usually also printed on the plastic cover on top of the engine. Be careful not to confuse it with the transom assembly serial - that's a different number and it won't give us your gear ratio.

It's stamped where the anode sits above the prop - take the anode off and you'll see it. If the unit is already off the engine, there's also a red plate in one of the internal cavities carrying the same number.

There's a red tag with our logo inside both the upper and the lower, in cavities you can't see while the drive is bolted together - we're looking for the 6-digit number on it. The same number is also stamped into the case: on the upper it's under the top cap, and on the lower it's on the underside of the cavitation plate, in the recessed area the trim tab anode covers. It's also on the original box if you still have it.

No - the speedo pickup can't cause water intrusion into the gearcase. The barbed fitting simply screws into the gearcase housing and connects to a rubber tube that runs up to the gauge. Remove that barbed fitting from your old unit and keep it for reinstallation on the new one.

It's much easier to pull the bearing carrier to replace them. We've heard of people doing it with the carrier still installed, but it isn't an approach we'd recommend. On MerCruiser applications the spanner wrench is the tool for removing the carrier.

It's straightforward. Take the old clip off your old driveshaft, set the shaft into the new unit, turn it so the splines line up and it will drop down part way. Then strike the top with a rubber mallet until it clicks home. The test is simple: if you can still pull it out, hit it harder. There's no video needed - the new unit already has a fresh retaining clip waiting inside.

Lubricate the seals, insert the shaft, line the splines up by feel and then strike the top of the driveshaft once or twice with a dead blow or rubber hammer. You'll hear a loud click. The shaft will still feel sloppy until the water pump is assembled - that's normal. You know it's correct when you can no longer pull the driveshaft back out.

It's held in by a retaining clip that has to be broken to release it. Secure the old lower unit in a vice, grip the driveshaft in the middle with a pipe wrench or vice grips, and strike upward against it with a rubber mallet to break the fingers on the clip. Your new unit already has a new clip inside: oil the seals, line up the splines and give the top of the shaft a tap or two with a dead blow or rubber mallet and it will click in. You know it's seated when you can't pull the shaft back out.

That's a very common problem and happens in the field constantly, because the plastic nipple gets brittle with age. The approach that works: when disassembling, cut the rubber line in two, then once the bellhousing is out of the way carefully cut the rest of the line away from both sides. Our own rule is that if a transom assembly is opened far enough for the bell to come off, the rubber line gets replaced as a matter of course.

The gap doesn't close until the shift shaft splines line up along with the driveshaft and water pump, so a gap that won't shut usually means the shift shaft hasn't engaged. The splines don't start until about halfway up the tube at the end of the shift shaft on the outboard. Bring the lower up until it stops, then have someone very gently jiggle the shift handle at the helm - it'll make the connection and let you bolt it up. Forcing it closed in gear is what leaves people stuck in reverse.

Yes - the speedo hole is drilled to the same pipe thread as the OEM; there's no reason for us to change the pitch. If your old fitting won't thread in cleanly, we'd recommend fitting a new OEM plastic fitting for the speedo port rather than forcing the original.

Almost always too much grease or debris packed into the shifter. Pull the unit back down and clean out the female shift coupler in the midsection. Then put only a little grease on the sides of the splines of the male shaft - nothing on top of the splines - and reinstall. That resolves the large majority of these.

This is almost always the shift shaft rather than the bolts. Take the unit back down and clean out the female portion of the shifter in the mid-section, then have someone gently wiggle the shifter at the helm as you bring the unit up - the splines are recessed in the female side, so it's hard to feel when you're actually lined up. If you're greasing the splines, put grease only on the sides, never on the top of the lower shift shaft. That resolves most of these on the Yamahas.

Work through it in order rather than forcing it with the bolts. Check the drive is in forward gear and that the gimbal bearing is aligned with an alignment bar, then confirm the alignment again with the engine rotated 180 degrees. Make sure no alignment pin has stayed behind in the transom assembly. If it still won't come up, stop there rather than forcing it - contact us and we'll work through it with you.

Three things to check, in order. First, make sure you don't have an alignment pin stuck in the midsection - if one stayed behind, the new unit can't come fully up. Second, have someone wiggle the shifter at the helm to confirm the shift shaft has engaged. Third, if it's in gear, turn the prop slightly to rotate the driveshaft and help the splines line up. Don't force it with the bolts.

On the Yamaha units, if the driveshaft is splining up correctly then it's either the water pump or the shift shaft holding it. The splines inside the Yamaha shift shaft don't begin until about halfway up, so it's easy to think you're engaged when you're not. Bring the unit up until it stops and have someone very lightly move the shifter at the helm to let the splines find each other. Also confirm the old and new gearcases both shift and turn the prop shaft in the same direction. On other brands the cause is usually different - contact us.

The most likely cause is that the shifter was past the forward detent when you installed the lower. Take the lower back off, find neutral on the unit, then install it with the boat's shifter in neutral. You may need someone to turn the engine over a tiny amount by hand to get the driveshaft splines to line up. We can send you the document that walks through finding neutral.

The dot exists to align a greaseable bearing with the grease port, so on a sealed bearing it doesn't matter and there's nothing to line up. What does matter is that the slots face toward the engine, and that it's driven in all the way. Beyond that there's nothing else to position.

Yes, use them - the bolts hold the unit up, but the dowel pins are what centre the gearcase. Ours are stainless steel. If a dowel has stayed stuck in your midsection, it's usually easier to remove the dowel from our lower unit instead: grip it with vice grips and twist while pulling up. They're not normally difficult to get out.

It varies - the gear position can change during shipping, so don't assume. Spin the prop shaft and work out which gear it's in before you install it, and lock it into forward before fitting the shifter. On a standard right-hand rotation unit, forward is with the shift shaft turned fully clockwise: the prop shaft then locks turning counter-clockwise and ratchets clockwise.

Thrust washer first, then the propeller, then the splined washer, then the nut, then the nut cover, and finally the cotter pin. Getting the thrust washer and splined washer the wrong way round is the usual cause of a prop that won't seat properly.

The prop nut is the same as the OE size - a 1-1/16" socket is what you need for tightening. Tell us which unit you have if you'd like us to confirm, and we stock the prop service kits if your hardware is due for replacement.

The two small black O-rings are the same part and go together on the shaft. The larger brown O-ring goes at the end of the splines that go into the engine coupler. If you're unsure, lay them out by size before you start - the brown one is easy to identify.

The water passage O-ring is obvious - it seats neatly in place. The driveshaft has three grooves: the two small O-rings go on the driveshaft where it passes through the gimbal bearing and have to stretch quite a bit to fit. The last one goes in the larger groove near the splines, though if your engine coupler isn't greaseable from the inside you don't need it. The big square-profile O-ring slides into the bellhousing.

On the newer units the plug below the prop shaft, on the bearing carrier, is the lowest drain - there's no separate drain hole in the bullet. Mercury moved to using only the bearing carrier drain on the newer units and we've emulated that, so if you can't find a bullet drain you haven't missed anything.

Because it has to go in first. Put the trim tab bolt in loose in the lower unit before you install the upper unit on top - once the halves are together there's no access to start it. That's normal for the design rather than a fault.

There's nothing different in the gearcase housing between the two versions, but beyond that conversion you have to stay with the ratcheting gear set. Ratcheting and non-ratcheting gears and clutches can't be mixed - we only work with the non-ratcheting gears and clutches in our own sets, so tell us which you have before ordering gears.

No, there are no adjustments in the lower unit for shift shaft travel. Start by confirming the basics - does the shaft point forward at the 12 o'clock position when locked in forward gear (driveshaft clockwise, prop shaft counter-clockwise)? If that's wrong and everything external checks out, the unit would need to come back to us for inspection and repair.

No - any replacement lower unit, whether ours or an OE one, is now 6-jaw, because the 3-jaw design was known to be problematic and neither we nor Mercury still build them. Our unit is the updated 6-jaw, so to fit it to a 3-jaw motor you have to swap out the shift linkage in the mid-section, and that means lifting the powerhead. We sell the shift shaft kit that goes with it. Plan for that work before you order.

Mercury switched from a 3-jaw to a 6-jaw shift system around the 1997 model year. Our SE205 is a 6-jaw lower - if your motor is the older 3-jaw type you'll also need the mid-section shift shaft kit (92-205-07K), and the powerhead has to come off to fit it. You can confirm by counting the reverse-clutch jaws, or look at the machined line just forward of the trim-tab bolt: straight across is 3-jaw, a 45-degree line is 6-jaw. Send us the engine serial number and we'll verify it before you order.

On a standard right-hand rotation unit: with the shift shaft turned fully clockwise, the prop shaft should lock when turned counter-clockwise and ratchet clockwise - that's forward gear. Neutral is neutral. With the shift shaft turned fully counter-clockwise, the prop shaft locks clockwise and ratchets counter-clockwise - that's reverse. Lock the lower into forward gear before installing the shifter into the upper, and check that it points straight out when in forward. That's the correct state to mount it to the boat in.

No, there's no specified measurement for shift rod movement - and no real reason for it to change, so if yours moves freely it should be fine. What does commonly go out of tolerance is the shift cables and shifter getting sloppy with age, which limits how far the shifter actually moves the rod. That's where we'd look first on a shifting complaint.

Work outward from the drive before assuming the unit. Original, worn shift cables are extremely common and are the single thing we see most - check the cables and control box are smooth and correctly adjusted, and that the handle being in neutral puts the drive in neutral. Also check the prop hub and the engine coupler, and drain the gear lube to inspect the magnet. Lower shift shafts do develop play between the brass bushings and the shift rod, and the seals that keep water out of the shift system are usually in poor condition by then - both worth doing.

It's specific to the engine model rather than universal - there's no single figure that covers the range, and the measurement only changes when the engine model changes. To take it: thread the shift rod into the gearcase, find neutral, then centre yourself in the middle of the play in neutral and measure from the mounting base of the gearcase to the eye of the shift rod, working it back and forth to confirm you're holding the centre. Tell us your engine model number and we'll give you the figure that applies to it.

Because the lever at the top of the shaft is a different length, which changes the overall throw of the clutch. Running a 6-jaw lower with the old 3-jaw throw doesn't engage the clutch correctly and can cause serious damage the moment you put it in gear under load. It's not an optional part of the conversion.

Our 422 and 429 units do have the water-cooled bearing carrier. If you're checking whether the cooling water passage from the anode through to the exhaust is present on the unit you're looking at, tell us which model you need and we'll confirm.

Yes - the needle bearing and both seals come installed in the carrier. The large outer O-ring is the one item not included with it, and we stock that separately. Add the cover nut and retainer if yours are worn.

Yes - the driveshaft bearing housing comes with the seals and bearing installed, and it includes the O-ring. One thing worth inspecting while you're in there: those two seals ride on a sleeve on the driveshaft, and that sleeve can crack. If it's split, new seals will leak straight through it - we supply a repair sleeve for our units.

On the MerCruiser bearing carrier, no - the large O-ring is a separate part, though we stock it and can add it to your order. On the Yamaha side it's different: the driveshaft bearing carriers come as a kit with the seals, O-ring and bearing included. Tell us which application you're on and we'll confirm exactly what's in the box.

Yes - the bearing carrier comes complete with its seals and bearings, so there's nothing extra to source for it. Tell us which engine you're working on and we'll confirm the right carrier for your gearcase.

We use the same corrosion protection approach as the original equipment, with bolt-on anodes, and our drives are finished in DuPont powder coat. Every drive was designed around the OEM drive and then tested against the OEM on our own research test lake to be equal to or stronger than it - a lot of hours and fuel have gone into that testing.

No - if the driveshaft is removed from our unit, that voids the warranty. Our units come built as a complete assembly and the driveshaft is part of that. On the applications where a driveshaft isn't included at all, such as the Johnson/Evinrude units, you'd buy the correct one from us rather than transplanting it.

No. Our driveshafts are made for our own units and aren't intended to go into an OE gearcase - if you're rebuilding an original unit you'll need to source an OE shaft. For understanding an OE gearcase in detail, the Johnson/Evinrude/OMC/BRP service manuals are genuinely good and we'd point you there.

Usually not - on most applications your existing upper driveshaft transfers straight across into our gearcase. It's the 1991-and-older models where a new one is needed. Send us your engine model number and we'll tell you which side of that you're on, and match the right part number to your shaft length if you do need one.

Yes, you can paint it to match and it will not void the warranty. Our units only come in black, so this comes up often on Yamaha and Johnson/Evinrude engines with a silver or grey finish.

No - all units ship dry. Fill it with gear lube before you run it. It comes with break-in instructions, and we sell the correct gear lube and a fill pump if you need them.

A complete gear set includes the pinion, forward and reverse gears, plus the bearings for the inner and forward gear. If you need shims or a clutch dog alongside them, those are ordered separately - tell us the gearcase you're rebuilding and we'll list what else you're likely to need.

Yes - the hardware is stainless steel, the same as the original equipment. The installation kit is worth having rather than reusing old fasteners, and you'll definitely need the new gasket that comes with it.

We strongly recommend it - it's the most-forgotten item on an order, and it's frustrating to be mid-job without it. It carries the mounting hardware, gaskets and the correct nuts, and on a Bravo lower it also includes a new driveshaft coupler. The studs in it are the correct length and matched to the OE part. It's a small addition next to the cost of a drive, and the gear lube kit is worth adding at the same time since every unit ships dry.

The installation kit has the gaskets, seals, nuts, and mounting hardware needed to install the drive or lower properly. We strongly recommend it with every complete drive or upper unit - it's the most-forgotten item on an order, and you'll want it in hand before you start.

The O-rings in the kit are used to mount the complete drive to the bellhousing. The seals needed between the upper and lower are already glued to the lower in the correct spots, so there's nothing to position there. Watch the nuts: the short lock nuts bolt the two drive halves together, while the normal lock nuts and washers install the drive onto the bellhousing. Also remember to drop the driveshaft coupler onto the driveshaft of the lower before you install the upper on top.

The aft bolt and the trim tab bolt from us are the same bolt. The short bolt in the kit with the star washer is what secures from the bottom up to the top half under the trim tab. Note the installation kit does not include a trim tab bolt as such - that's supplied with the anode kit instead, which catches people out when they're replacing a factory MerCruiser drive with ours.

Yes - all of our SE116 gearcases use the remote oil bottle exactly as the OE units did, so if your boat has the reservoir in the engine compartment it will connect up the same way. Fill from the bottom up through the drive so the level reaches the bottle without trapping air.

Yes - for our SE116 drives, for example, we sell the vertical driveshaft, bearings, carrier assembly and upper seals individually. For gearcases we generally sell seal kits and water pump kits; gears and bearings vary by application, with some sold individually rather than as kits. Tell us the unit and what failed and we'll tell you what's available.

Not currently - for Suzuki we sell complete lower units rather than individual components such as prop shafts or gear sets. Note also that removing the driveshaft from one of our units voids the warranty, so transferring parts between units isn't something we can support.

It takes the same hub kit as your OEM gearcase did, so if the prop was working on the old unit the same hub kit carries over. We don't hold the Mercury part numbers for the hub kits, so source that from a Mercury dealer or the prop manufacturer. The exception is where you're changing case type - moving off a Torque Master, for example - which needs a different hub because the prop shaft diameter changes.

Yes - the gears are hardened to a 62 to 65 Rockwell specification, which is what the application requires. Our parts are manufactured to OEM specification and inspected, including X-ray inspection to confirm the material matches.

Yes. Yamaha seals will work in our units - there's no difference other than ours being aftermarket. If you'd rather source them from us, tell us which unit and which seal and we'll point you at the right part.

There's only one seal between the two halves - a quad ring that sits in an oil passage, and it should already be on your drive out of the box, so just confirm it's there. Apart from that quad ring there are no other seals between the upper and lower sections. The installation kit we sell carries the hardware to bolt the units together, a plastic water pump guide tube and the mounting gaskets that mount the drive to the boat.

There's no gasket - just a small O-ring, sometimes called the quad ring. Don't reuse the old one. If you're buying a lower unit or a complete drive it comes included, so there's nothing to add. If you're buying an upper on its own, add the O-ring to your order - it's the part people most often get caught out by.

The lower comes with the O-rings that go between the upper and lower housing, so the joint itself is covered. What you may also want are the mounting gaskets and O-rings for fitting the upper assembly to the transom assembly - we list those separately under our OMC Cobra upper gaskets and seals. Tell us what you're taking apart and we'll list the set.

Yes. The 25" SE205 includes the taller shift shaft that makes up the extra five inches, so there's no separate shaft to buy. Give us your engine serial number and we'll confirm the exact unit for your motor.

No, a skeg guard isn't included, but we do sell one that fits. Note the skeg itself is simply the fin-shaped bottom of the lower unit and is part of the casting - the guard is a separate bolt-on piece that protects it from impact damage.

On the OMC applications, yes - the thrust washer needs to change to the 1-1/4" size, and that's typically the only change required. We sell the thrust washers intended for stock propellers. If you're running an aftermarket brand prop, we'd recommend getting the thrust washer that brand makes so the fit is right.

Our thrust washer is intended for OE propellers, and the fit is sometimes different with an aftermarket prop. If you're running a Turning Point, Solas or similar, get the thrust washer from whoever made the prop to guarantee the fit - you may need a complete hub kit rather than just the washer. On the newer outboards the thrust washer comes from the outboard side.

No, it's the same taper as the Yamaha shaft, so your original thrust washer should go straight on. Slide it into place and send us a photo if it still looks wrong, and let us know whether the prop was changed at the same time - a different prop is the more likely culprit than the taper.

Our thrust washer works with OMC three-blade props. OMC used a different thrust washer for four-blade props, so if you're running a four-blade you'll need that one instead. And if the prop isn't an OMC prop at all, get the thrust washer from whoever makes the prop - the taper and hub differ between manufacturers and that's the usual reason a washer won't seat.

No - our transom assemblies are new aftermarket replacements, built with the same aftermarket parts we make and sell on our own website. The anodes fitted to them are the same aluminum anodes the original equipment assemblies came with.

Yes - it comes with all the bellows already installed, the gimbal bearing, trim cylinders, hoses, anodes, trim senders and the foam gasket that goes against the boat's transom, plus all new hardware. It bolts up exactly as the original does. The exceptions are SmartCraft sensors and the Mercathode, which are Mercury-specific and have to be transferred over.

It's a complete assembly - all the bellows come already installed, along with the gimbal bearing, anodes, trim senders and the foam gasket that goes between the gimbal housing and the boat's transom. It bolts up exactly the same as the original and comes with all new hardware. The one thing not included is the Mercathode, which is a Mercury-only product, so that has to be transferred over or bought new.

Yes - our trim units are pressure tested before shipping and they come with fluid already in them. Air can work its way in during transit since the boxes end up on every side, so if it feels spongy on arrival, bleed it with the manual valve shut, cycling up and down and refilling, then check the final level trimmed all the way up.

Yes, ours have both low and side water intakes. Some of the older original units didn't, so if you're matching to an existing setup it's worth checking what yours has. Tell us your engine serial number and we'll confirm the right unit.

Yes - OEM water pump kits and driveshaft seals work fine on our units, since ours are made to OEM specs and interchange with OE parts. If you're changing the driveshaft seals, take the opportunity to inspect the collar the seals ride on, as that's a known crack point and it will leak again through brand-new seals if it's split.

No - there's no difference between an SEI and an OE water pump assembly. We keep our gearcases dimensionally the same as the originals so OE parts swap over without issue. Buy whichever is convenient; we stock the water pump kits if you'd rather get it from us.

No, the kits from us and from Mercury both come without printed instructions - the procedure is in the MerCruiser service manual, which is also available online. If you get stuck partway, contact us and we'll talk you through the order the parts go in.

On our Mercury and Yamaha outboard lower units, yes - the complete water pump assembly (including the impeller) comes installed. Alpha sterndrives include the water pump too. Bravo drives, OMC Cobra, and Johnson/Evinrude lowers do NOT include a water pump (those pumps live elsewhere), so you'll reuse or buy that separately.

On almost all our drives and lower units, yes - where the water pump lives in the drive, it comes installed complete with the impeller. The Yamaha and Mercury complete lowers arrive with the water pump fitted. The exceptions are the Johnson/Evinrude and OMC applications, where the pump lives elsewhere and isn't included. None of them come with gear lube, which you supply.

Send us the kit number or your engine model and year and we'll give you the full fitment list - our kits cover specific gearcase ranges rather than broad model years. As an example, one of the OMC kits covers a run of mid-1970s 50 and 55 HP Johnson and Evinrude gearcases. If we don't have a particular small bearing or seal for an older Cobra, we'll tell you honestly and point you elsewhere.

Yes, the upper driveshaft on your current lower can normally be reused, and we can send you instructions for extracting it. You can also reuse your existing shift rod. If either turns out to be worn, we stock replacements.

On the applications where they aren't included, yes - remove both from the old unit. The driveshaft lines up on the splines and taps in with a rubber mallet until it clicks home. The shift shaft unscrews from the old unit and screws into the new one. On other product lines, such as the Yamaha complete lowers, the water pump, upper driveshaft and shift rod arrive already installed.

No printed instructions are included. For the MerCruiser applications we'd point you to the MerCruiser service manual, and for Johnson/Evinrude the OMC/BRP manuals are excellent - many are available online. The OMC Cobra conversion kit is the exception and does come with directions. The break-in procedure is on a tag attached to the prop shaft.

The lower arrives with the seals needed to join the upper and lower halves together, so it will go together without one. The installation kit adds the new driveshaft coupler plus the hardware to bolt the halves together and the mounting gaskets - we'd recommend it rather than reusing an aged coupler.

No - the lower unit doesn't include install hardware, anodes or gear lube. Those are ordered separately, and we stock all of them. Tell us which Cobra you're working on and we'll list the few items you need alongside the lower.

Yes - the lower unit arrives with the lower driveshaft and retaining clip already in place and ready to go. You extract your original upper shaft from the old gearcase (which breaks that clip), lubricate the driveshaft seals, insert the shaft into the new gearcase and give the top a hit or two with a dead blow hammer until it clicks in. You'll know it's right when you can no longer pull the upper driveshaft back out.

Yes it does, and the fitting ships loose inside the box rather than installed, so that it doesn't get damaged in transit. Don't throw the packaging out before you've found it.

No - the complete ships in two halves, which protects it in transit and keeps it out of freight shipping. It doesn't include install hardware, anodes or gear lube. One thing not to forget on assembly: there's a coupler that goes between the upper and lower on the driveshaft splines. It's in the installation kit, or you'll need to pull it off your old drive to reuse.

It comes with the exhaust gasket, but the anode is not included - that's available separately and is listed further down the same product page. Tell us your model number and we'll confirm exactly what's in the box for your unit and what you'd want to add.

It arrives complete with the water pump installed, but shipped dry - you supply the gear lube. Everything else you need is either transferred from your old unit or available as an add-on: the installation kit and an anode kit are the two we'd recommend with every order. Follow the break-in procedure on the tag attached to the prop shaft.

Essentially yes, on the complete lower units - fill it with gear lube, bolt it up, fit your prop and go. Reuse your existing accessories and anodes or buy the anode kit separately, and follow the break-in procedure on the tag attached to the prop shaft. The installation kit is worth adding so you're fitting fresh gaskets and hardware rather than reusing aged parts.

It's the connector for the speedometer, and it isn't included with the lower unit. It connects to the shift bushing on the lower. Your boat may already have it on the old unit - if yours has the same nipples as the current-style fitting, you can transfer it across. Send us a photo if you're not sure and we'll confirm.

Yes. None of our drives include installation kits or anodes as standard, because some customers prefer to reuse their existing parts. The installation kit is where the hardware lives - including the washer that sits over the splines on the lower shift rod, beneath the brass shift lever. If your shift lever sits too low to engage, that missing washer is usually why.

On that unit you reuse your existing shift shaft, upper driveshaft and water pump - it comes just as pictured without those. That makes it a cheaper swap than the applications where the driveshaft has to be bought new. Send us your engine model number and we'll confirm which of the SE306 variants you need.

It arrives with the water pump, upper driveshaft and shift rod already pre-installed, so it's largely bolt-on. It does not include installation hardware, anodes or gear lube - you reuse your existing accessories and supply the lube. Fill it before you run it, since every unit ships dry.

Our J/E units don't include the water pump, upper driveshaft or shift shaft. Most customers need the upper driveshaft as a separate item, plus a correctly sized thrust washer for the prop, and a water pump kit if the old one isn't serviceable. The shift rod can usually be reused. Tell us your engine model number and we'll list exactly the three or four items you need.

Our Johnson/Evinrude units don't come with the upper driveshaft, the shift shaft or the water pump - you either transfer those from your old gearcase or buy them separately. We stock the water pump kits and driveshafts if you need them. Depending on the application you may also need a correctly sized thrust washer for your prop.

A fine, glitter-like or fuzzy deposit on the magnet is normal through the first 10 hours - that's the bearings, races and gears wearing in together. What's worth a closer look is larger chips or a heavy quantity. Send us a photo of the plug along with your unit serial number and hours and we'll help you tell the difference.

Usually not. We use an assembly grease during the build that's typically blue in colour, and once the unit is filled with lube and run, that grease mixes in. Seeing a coloured, cloudy lube at the very first change is normal. If you're not satisfied that's the explanation, a pressure or vacuum test to a maximum of 15 psi held for 15 minutes will tell you whether the gearcase seals are sound - and you're welcome to send us photos.

Bravo drives are tight to shift when the engine isn't running, so check whether you're testing it that way first. Our drives are also a "high bump" version of the Bravo, so a firm shift in and out of gear is expected and normal in operation. Drives do loosen up after break-in. It's still worth verifying your shift cables are in good condition and moving freely.

Yes, that's expected at first. The gears haven't been broken in to one another yet, and the bearings, races and gear faces all still have to wear together. Once it goes through proper break-in - and particularly once it runs under load - we expect it to quiet down to a normal level. This is exactly why the break-in procedure matters on any new mechanical assembly.

That's normal out of the water. With no water load there's no pressure on the propeller to keep the clutch engaged smoothly, so you'll hear and feel it engage. It's much more noticeable with a heavier stainless prop than with aluminium. If it behaves normally once the boat is in the water under load, there's no issue.

For the first 5 hours, don't hold a constant RPM - vary it every 5 minutes or so - and don't exceed 75% throttle. Shift into forward and reverse at least 10 times during those first 5 hours. Between 5 and 10 hours, do short runs at full throttle. After 10 hours you can resume normal operation, and you must change the gear lube somewhere between 10 and 20 hours. Keep the load light and start slow and low for the first few hours.

There are two tags on the prop shaft. One carries the break-in instructions and the other states the unit is shipped without gear oil. Beyond installation, filling it with marine gear lube is the one thing you must do before running it. When mounting, pay attention that the gearcase and shift linkage spline up and everything goes together without binding.

For the first 0-5 hours, run at lower RPM and gradually work up. From 5-10 hours, keep full-throttle bursts to just a few minutes per hour. Then change the gear lube at 10-20 hours - don't skip that first change. A little glitter-like metal on the magnetic drain plug at that first change is normal.

By a wide margin it's improper break-in, or the gear lube not being changed often enough and becoming burnt and gritty. The change at 10 hours after break-in is the one we see skipped most often, and skipping it is what turns a healthy unit into a failed one. Follow the break-in tag and do that first change on time.

They come with the unit - there's a tag attached to the prop shaft with the break-in procedure printed on it. If that tag has gone missing, contact us and we'll send the procedure over.

Always fill from the bottom up so you don't trap air. Pump lube in through the very bottom plug until it comes out of the top plug on the upper, then install that top plug and keep pumping until the lube shows at the proper level in the gear lube bottle. Then remove the pump and install the bottom plug. Getting to the full level matters - an underfilled unit can fail early, and a single quart is definitely underfilled on a sterndrive.

Yes, and this catches people out. We've seen Suzuki units come back underfilled because the third vent plug wasn't used during filling - the unit reads as full without it but isn't. Make sure you're using all the fill and vent points when you fill it, because an underfilled gearcase can fail early.

With the boat sitting in the water off the trailer you should be fine in theory, but we'd keep it on the trailer with the straps on so you can get higher than the normal waterline - aim for an extra 6 inches to a foot depending on the boat. It's also worth putting a little dish soap on the impeller when you install it so it's slippery on that first dry turn.

Yes, no issues at all - OE gear lube and OE grease are both fine on our outdrives. You don't need a special SEI-branded fluid. We do sell the correct gear lube and a fill pump if it's easier to add it to your order.

No. You can use any GL-4 (semi-synthetic) or GL-5 (full synthetic) rated 80/90 or SAE 90 marine gear lube in our units, exactly as with the OE gearcases. We sell our own lube and the drain washers if it's convenient to add them to an order, but the drain gaskets are the same ones used on almost all lower units and are widely available.

Start by draining the gear lube and pressurising the gearcase to 10-15 psi to confirm where it's actually escaping. When they leak from that side hole, the source is most often up under the water pump and driveshaft area rather than at the point you can see. Let us know your purchase date and serial number and we'll check whether it's within the warranty period.

It can. Most marine-grade gear lube will emulsify with water, so while the unit is running every bearing is being fed the same diluted, poor-quality lube. When you stop, it separates over time and the water settles to the bottom - which is where the lower bearing sits. The longer it runs that way, the more likely there's damage.

That's water intrusion, and the first step is to find where it's getting in. Drain the lube, then pressure test the gearcase to 10-15 psi and spray soapy water around the seals - the bubbles will show you the leak. On a sterndrive, a failed bellows is a common cause rather than the unit itself. Get the SEI serial number off the unit and contact us so we can check your warranty status and start a claim if it's covered.

Quicksilver or Mercury High Performance gear lube is what we point people to. Specification-wise we recommend an 80/90 semi-synthetic rated GL-4, or a straight SAE 90. All units ship dry, so it needs filling before you run it.

Use Mercury or Quicksilver High Performance gear lube (a straight ~90 weight) - as long as it says "High Performance" you're good. Fill to the top vent hole with the drive/motor level; an underfilled unit can fail early. Capacities vary by model, so check your unit's spec or ask us.

Once a year. The main reason is the water impeller, but with the drive off it's also the right time to check the transom components and grease the U-joints. Marine-grade grease is preferred, though most tube greases will do the job. For gear lube, stay with a marine-grade 80/90W or SAE 90.

Every year or every 100 hours, whichever comes first - and sooner if you've been running in sand or silt. Replace the whole water pump kit rather than just the rubber impeller: the kit contents are plastic and the base of the pump also seals the driveshaft, so renewing one part of an aged assembly is false economy. While you're in there, inspect the driveshaft collar for hairline cracks.

No, and it would defeat the purpose - the trim tab on an Alpha drive is sacrificial, so painting or coating it stops it doing its job. It's supposed to corrode instead of your drive. Leave it bare and replace it when it's consumed.

No. There's an access hole above the anode - put a 3/8" Allen key through it and remove the bolt that holds the anode on. The bolt itself stays captured between the two halves, but you can reach and turn it through that hole, so the drive stays together.

No. An older Bravo carries a single anode that mounts under the cavitation plate, and it doesn't use the round anodes found on the later drives. That's why the anode kits are split by era - fitting the newer round anodes to an older drive isn't correct.

Yes, the flat (no-fin) trim tab anode is available, but it's sold separately rather than as part of the anode kit. Add it alongside whichever anode kit matches your lower unit.

Anodes are sold separately from the lower unit. We offer a complete anode kit for each unit family, and if you only need one piece - the rectangular bolt-on anodes, for instance - we sell those individually along with the correct bolt and nut. Tell us which unit you have and we'll send the exact part numbers.

No - that isn't needed. The trim cylinders are grounded to the rest of the transom assembly through the mounting bolts, which makes all the electrical connection the anodes need. Stripping the paint won't improve protection, and if anything it just gives corrosion a place to start.

Zinc is the choice for salt and brackish water, aluminum for fresh, and magnesium gives the best protection in fresh water specifically. Our kits come in different materials for exactly this reason, so tell us what water you boat in and we'll match the kit to it.

We carry both the trim tab anode and the lower unit anode for our OMC-application units (SE304, SE305 and SE306 families). Tell us which lower unit you bought and we'll link the matching trim tab anode and anode kit.

There are two Bravo Three anode kits - one for 2004-and-up drives and one for pre-2004 - so check which era your drive is before ordering. Also read the kit description carefully, because one version is zinc and the other is aluminum. If you tell us your drive and where you boat, we'll point you at the right one.

The SE405 anode is the trim tab for the 115 applications. As with all anodes it's sold separately from the lower unit. Send us your outboard model number and we'll confirm fitment before you order, since the anode differs between our unit families.

It depends on the year of your transom assembly. A quick check: if there's no grease zerk on the starboard side of the transom assembly, you want the sealed bearing version of the kit. Tell us the boat year and which drive is on it and we'll send the right one - we offer the Gen II bellows kit in both greasable and sealed configurations.

Yes - we sell a great many of them. As with any component in salt water, apply corrosion spray to the unit initially and then annually, and wash it down properly after use. Anything that actually sits in salt water rather than being trailered should also be painted with a coating intended for that.

If the boat sits in salt water permanently, it's worth using a copper-free antifouling paint made specifically for outdrives - copper-based bottom paints accelerate corrosion on an aluminium drive. Keep up with anodes, touch the paint up yearly, and rinse and clean the drive regularly. Those habits make a bigger difference over a season than anything else.

A drive shower sprays water over the drive while you run. We recommend it if you get the boat up on plane and keep it there for longer periods, since that's when the drive gets the least cooling water over it. It's an inexpensive add-on and it's listed in the related items on the drive's product page.

Yes - we sell a kit that comes with 2 quarts of gear lube and the fill pump, which is the easy way to cover it in one order since every unit ships dry. It's listed in the related items at the bottom of each drive's product page.

The Bravo is typically a sealed bearing. If you'd prefer a greasable one, the Alpha greasable bearing is the part to use. When ordering a bellows kit we'll ask which you need, because the kit differs between the two.

The Gen I always came with a greasable gimbal bearing, so if you'll keep up with greasing it, staying with greasable is fine. If you'd rather have one less thing to think about, a sealed bearing is a good upgrade - remove the zerk and plug the grease passage. Check which you've bought: a greasable bearing still needs grease added through the zerk on the transom bracket.

We don't make propeller recommendations - we're not prop specialists and the right choice depends on your hull, load and how you use the boat. A local prop shop is the right place for that conversation. What we can tell you is your gear ratio and shaft length, which are what the prop shop will need from you.

The two most-recommended add-ons are the installation kit (gaskets/seals/hardware) and the anode kit. Depending on how you run, a skeg guard and a drive shower are also popular. They're all listed in the "related items" on each product page, and we stock everything you'd need.

At minimum you'll want the installation kit, which carries the gaskets, seals and mounting hardware, plus an anode kit since anodes aren't included. We offer zinc anode kits for salt and brackish water and aluminum for fresh - let us know which you're in and we'll match it.

With the drive off you have easy access to parts that are a lot of work to reach later, so it's worth inspecting the bellows, the trim cylinders and the shift cable while you're in there. We sell bellows kits and trim cylinders if any of them are due. It's much cheaper to replace a marginal bellows now than to pull the drive again in a season.

The two we recommend on almost every order are the installation kit (gaskets, seals and hardware) and an anode kit - anodes are not included with the unit. Depending on how you run the boat, a skeg guard and a drive shower are popular additions, and you'll need gear lube since every unit ships dry. On each product page you can scroll down to the related items and see everything that goes with that unit. We stock all of it, so it can ship together.

A torque tab is no problem on our lower units. The one caution is that any modification becomes your responsibility if it causes a failure - for example, if a hydrofoil is fitted and someone steps on it and cracks the case, that break isn't a warranty item. Beyond that disclaimer, we have no issue with them.

Yes. One Yamaha skeg guard covers our SE416, SE418, SE421, SE422, SE428 and SE429 lower units, and we make separate guards for the SE404 and SE405 as well. Tell us which unit you're running and we'll confirm the right guard before you order.

It depends on the gearcase, not the horsepower or year - for example a Magnum gearcase takes the guard made for our SE316/SE318 units. Send us the full engine model number and we'll tell you which gearcase you have and therefore which guard fits. Any guard that fits the SEI unit for your engine will also fit your original gearcase.

The skeg guards are matched to the lower unit family rather than to horsepower, so the guard that fits an SE206 is different from the one that fits an SE216/218/221. Check the notes on the guard's product page and verify which size gearcase you actually have before ordering - if you're unsure, send us your engine serial number and we'll confirm.

No. The Bravo doesn't use the seals that driver is made for, so the Alpha seal driver won't do the job. Tell us which Bravo seal you're replacing and we'll point you to the correct tool.

Removal is normally done with a standard slide hammer and a two-jaw puller attachment rather than a dedicated tool. For installation we sell the gimbal bearing driver, but you'll also need an alignment bar for our adaptor to work against. The driver slides over the alignment tool or drive rod and drives the bearing into the transom assembly.

Yes - our tools section covers the bearing retainer wrench, spanner wrench, hinge pin tool, bellows expander and sleeve installer, slide hammer, pinion bearing driver and driver rods. Tell us which drive you're working on and which seal or bearing you're after and we'll point you to the right tool.

Yes - our Tools page has the seal and bearing tools for our drives and lowers. If you're not sure which tool you need, tell us the drive you're working on and the seal or bearing, and we'll point you to the right one.

No, there's no drilling required. The driver slides over an alignment tool or drive rod and is then driven into the transom assembly. Some people mark the grease zerk location at the four o'clock position on the tool or bearing with a marker, but that's just a reference mark, not a modification.

Use a two-jaw setup with the claws facing outward. Insert it into the gimbal bearing, tighten it so the jaws grip, then slide-hammer it out. A standard slide hammer with a two-jaw attachment does the job - there's no dedicated puller needed for removal.

First, get the service manual for the Alpha One Gen I - you'll need it for a job like this. Beyond that, the tool list depends on how far you're going: doing seals only needs far fewer special tools than doing bearings, which needs a considerably larger set. The best approach is to disassemble the drive first so you know what's actually worn, then buy to that list. We keep a list of the tool numbers and can send it over.

That puller is a universal tool but it's typically used on the V6 gearcases, so on a small gearcase like a 40 or 50 HP it's likely to be too large and we can't promise fitment. Tell us the engine and gearcase you're working on and we'll say whether it's a realistic fit before you buy it.

No, the lines aren't included with the cylinders - they're separate parts. You'd typically need two of the hydraulic hoses plus one port and one starboard hose, and the connectors. Tell us which drive you're on and we'll list the exact set for your application.

No - the Yamaha OEM trim caps are different and will not fit our TT6007 trim system. We sell the replacement lower caps with seals as our Trim Cap Kit, and there's also a Tilt Cap Kit (part 9C-416-71K) that isn't listed on the website - contact us for that one. Note this is different from the lower units, where Yamaha OEM seals and water pump kits do interchange with ours.

Yes, though many of them aren't listed on the website - ram caps with seals, snap rings, manual release screws and similar are available but have to be ordered directly with us. Contact us, tell us the trim system you have and exactly which pieces you need, and we'll quote them.

Yes - we stock trim motors across several applications including Yamaha SHOWA systems and OMC/Johnson/Evinrude systems, and we cross-reference by OE part number. Send us the OE number or your engine model and year and we'll confirm a match and current stock.

Yes, you can change just the end cap. It's a little tricky because you have to keep the pinion assembly together while disassembling it. If you'd rather replace the whole cylinder we stock both port and starboard versions for Gen I and Gen II - tell us which side and which generation and we'll link the right one.

The TT6016 covers a number of the larger Yamaha and Mercury four-stroke applications - it's cross-referenced by OEM part number rather than by horsepower alone. Send us your engine model number or the OEM trim assembly number and we'll confirm the match and current stock. Trim systems carry a 1-year warranty.

Our TT6007 covers Yamaha trim systems from 1998 up across 115 to 250 HP, and OEM numbers such as 6CB-43800-01-00 cross to it. Give us your engine model number or the OEM trim part number and we'll confirm the cross-reference. Trim systems carry a 1-year warranty and ship pressure tested with fluid already in them.

We focus on drives, lower units, and the related parts we manufacture and stock - we don't carry items like shift/throttle cables or fuel-line adapters. If you tell us what you need we'll be honest about whether it's something we have.

For outboards we sell complete, new lower units rather than rebuild kits. We do offer seal and bearing kits for many drives, so tell us your model and what you're trying to repair and we'll let you know what's available.

Order now. Placing the order secures your place in line, and these go out strictly first come, first served as stock arrives. You can always cancel for a refund if the date moves somewhere that doesn't work for you, though you'd lose your position. Estimated ship dates do shift a little with shipping schedules, so treat them as close rather than exact.

The billing address has to match the address your card statement goes to (the shipping address can be different - the site accepts both). If it still won't go through, verify the billing address your bank has on file, or contact us to place the order directly.

Usually yes, as long as it hasn't shipped - contact us as soon as possible and we can add it to the existing order with no additional shipping cost. Tell us if you'd like the order held so you can add something.

Yes. Place the second order and choose local pickup as the shipping option so it doesn't charge you shipping, then let us know - we'll ship it together with your original order. That saves paying a second shipping charge on a small tool or part.

Yes. SEI Marine Europe ships to customers throughout the EU from our Považská Bystrica, Slovakia warehouse, priced in euros with VAT applied per destination country. Add the item to your cart and enter your address to see the exact shipping cost and delivery estimate before you enter any payment details.

Yes, we can ship to most of Europe, though customs, duties and VAT may apply on delivery depending on your country. Add the item to your cart and enter your address and the site will quote it. If you're in the US, Canada, or elsewhere outside Europe, order instead from our US operation at sterndrive.cc, which is priced in US dollars and ships from Florida.

No - order from sterndrive.cc instead, our US operation based in Florida. It's priced in US dollars and is the faster, cheaper route if you're in the US, Canada, or otherwise outside Europe. seimarine.eu exists specifically to give European customers local stock, shipping and warranty support.

The country of origin is Taiwan, where our units are assembled in our own factory, before being distributed through our Slovakia facility for the European market. We can't tell you what a particular non-EU border will assess, but that's the figure customs will be asking for.

VAT is applied based on your destination country and shown at checkout before you pay - it isn't buried in the listed price. Within the EU this is handled automatically; outside the EU, duties and import VAT are generally collected on your end when the package is delivered.

Yes. We're at Robotnícka 389, 017 01 Považská Bystrica, Slovakia. Place the order online and choose the local pickup shipping option, and we'll have it ready - in-stock items are usually ready within 1-2 business days.

Place the order online first - pickup isn't something we can do on a walk-in basis. At checkout choose the local pickup shipping option, which removes the shipping charge. We'll have it ready for you at Robotnícka 389, 017 01 Považská Bystrica, Slovakia; in-stock items are usually ready within 1-2 business days.

Place and pay for the order in advance and choose local pickup as the shipping option - we can't do walk-in sales, because the order needs processing and picking before it's ready. Our warehouse hours are 7:00 AM-2:00 PM local time on business days.

A single small seal or O-ring usually falls below our minimum order value. Two options: add something else you'll need anyway to reach it, or take the OE part number from our product page and pick it up from a local dealer. We'd rather tell you that than have you waiting on us for a two-euro part.

Because the warranty is attached to the unit against your engine. We verify the serial matches the gearcase being shipped so that the right part goes out with valid cover - without that check we can't provide the warranty. It's also the last chance to catch a ratio or shaft length error before a unit that can't be returned once installed leaves our warehouse. Orders are held rather than shipped until we have it.

Almost always because we need to verify the engine serial number before shipping. We check the serial against the unit ordered so the right part goes out with a valid warranty attached - if the information supplied doesn't match the unit, we hold rather than ship the wrong thing. Reply with the serial number off the engine and we'll release it, often the same day.

Standard card payment methods are accepted at checkout in euros. If you have a question about a specific payment method or a dealer account, contact us and we'll confirm what's available.

No - once a drive or lower unit has been bolted up it can't be returned. That's exactly why confirming your gear ratio before ordering matters so much; on a drive it's an expensive mistake to get wrong. If there's any doubt, send us your drive serial number or a gear tooth count first and we'll verify it.

Contact us about return shipping - if you still have the original packaging we can usually make it easier. Whichever way you ship it, write the RMA number on the outside of the box so we can identify it when it arrives. You're welcome to use your own courier instead if you prefer.

It's returnable as long as it's in new condition - no gear lube added and not mounted to the boat. There's a restocking fee, freight isn't refunded, and you'd be responsible for the shipping cost back to us. Once a unit has been bolted up it can't be returned at all, so it's always worth confirming rotation and ratio with us before ordering.

Returns are accepted within 60 days for a new item in resalable condition. Once a unit has been installed it isn't returnable except under warranty, and adding gear lube counts as used. There's a restocking fee, the original shipping isn't refunded, and you cover the shipping back to us. Write the RMA number on the outside of the box so we can identify it when it arrives.

Contact us in writing before the order ships if you'd like the signature requirement waived - bear in mind that means the courier can leave a large, heavy box unattended.

For higher-value shipments, yes, a signature is typically required on delivery. We can ship to any address you provide - including a business or a marina - as long as someone is there to sign for it. That's worth planning for on a large item.

If a unit arrives damaged, do not install it - take photographs of the damage and send them to us and we'll handle it from there. Installing a damaged unit is the one thing that makes it hard for us to put right.

Complete sterndrives always ship in two boxes. Splitting them that way keeps them out of freight shipping, which saves you a significant amount on shipping cost and weight. If you've only received one box, check your tracking - the second is usually in transit right behind it.

Two reasons: it avoids damage in transit, and it keeps the shipment out of freight, which saves you a significant amount on shipping compared with one oversized crate. The upper and lower go back together with the seals already in place on the lower - the installation kit has the short lock nuts for joining them.

Smaller parts orders ship free once they pass a certain order value, so if you're just under it, it's often worth adding something you'll need anyway - a shift cable or a seal kit, for example - rather than paying the shipping fee. There's also a minimum order value, so very small single items can't be ordered on their own. The cart shows you where you stand before checkout.

Add the item to your cart and enter your shipping address - the website calculates the cost and shows you the delivery options without asking for any payment information. Rates change from time to time so the checkout figure is the accurate one. If you'd rather not, contact us with your postcode and we'll quote it.

There's a minimum order value, and smaller parts orders ship free once they pass a higher threshold - the cart will show you both as you add items. Large items such as lower units, drives and transom assemblies are always priced by their size and weight because of courier dimensional charges, so those carry a shipping cost regardless of order value. Contact us if you'd like the current figures.

In-stock items ordered during business hours typically ship within a business day. How long it then takes depends on where in Europe it's going - tell us your postcode and we'll give you a real figure, or the website shows it at checkout.

Orders shipped from our Slovakia warehouse typically take 3-5 business days across the EU. Stock varies by product, so if you need to confirm availability or a restock date, contact us.

Typically 3-5 business days across the EU from our Považská Bystrica warehouse, depending on your distance from Slovakia. In-stock orders placed during business hours usually ship within a business day.

Orders placed during business hours (7:00 AM-2:00 PM local) on a business day usually ship the same or next business day, as long as the item is in stock. We're closed weekends, so a Friday afternoon or weekend order goes out the following business day.

Yes, please ask. We hold inventory and it's occasionally been the case that an item shows unavailable when we actually have it. Contact us with the SKU and we'll check properly and tell you either the real stock figure or the current estimated ship date.

Contact us with the part number and we'll check it and send you a direct link to the item if we have it - you can then order online from there.

No - everything we sell is brand new aftermarket, and we don't carry used units. Occasionally we have a returned unit we can sell for a little less, so it's worth asking if budget is the constraint. We also don't accept cores, so there's no exchange programme.

Not necessarily. Some units are in our range but not listed online yet, particularly newer models. Contact us with your engine model number and we'll check properly.

That feature is still being worked on. In the meantime, put your engine model number directly into the search bar at the top of the page and it will take you to the correct unit if we make one. Then check the technical or application tab on the product page to confirm your model number and year are listed. If nothing comes up, contact us with the model number.

Everything we sell is brand-new aftermarket, not rebuilt or refurbished, and no core is required or accepted. Keep your old unit - someone who deals in used parts may pay you something for it. The new unit carries the 3-year fault-free warranty as long as it isn't used for commercial, tournament or rental purposes.

No core charge. We only sell brand-new units, so there's nothing for us to do with an old core - you keep it.

No core charge and no core return required. We only sell brand-new aftermarket units, so a used core is of no use to us - you keep your old one and can dispose of or recycle it however you like.

No - we only sell new aftermarket units, so we don't accept cores and there's no core credit. You keep your old unit and can do as you like with it; someone who deals in used parts may give you something for it.

A little fine, glitter-like metal (especially at the first break-in oil change) is normal. Larger chips or a heavy amount is worth a closer look - send us a photo of the plug and tell us your motor/drive and hours, and we'll help you tell the difference.

That's usually the remains of a burnt-up impeller. Those small rubber pieces work their way up through the system, and we almost always find them between the engine and the transom at the power steering cooler. If you've had an impeller fail, check that cooler for debris before you chase an overheat any further.

Run the boat with the drive off. In a shop we'd pull the hose from inside the transom assembly and feed a garden hose into the hose going to the engine so it has cooling water. Run it up and listen: if the noise isn't there with the drive removed, then you know to start looking at the drive. If it's still there, the drive isn't your problem.

Start by checking whether the propeller is making contact with the gearcase, particularly if the prop was off during a recent repair. A noise that appears only in forward gear and disappears in neutral at any RPM points that direction before it points at the gears. If there's also metal in the lube, stop running it and send us photos of the drain plug magnet.

Check the coolers and water passages for debris, and in particular the power steering cooler, which is the one that tends to get plugged when an impeller disintegrates. Pieces of vane travel downstream and lodge where the passage narrows. Clearing the pump but leaving the debris in the cooler is a common reason an overheat persists after an impeller change.

It's common practice in the field to use a seal retaining compound on prop shaft seals - we use red Loctite, applied as a small coat around the outside of the seal before it goes into the carrier. For finding the leak itself, pressure test the unit and use soapy water around the seals so the bubbles show you exactly where it's escaping.

Start with the prop hardware. Recheck it and specifically confirm the thrust washer is fitted behind the propeller on the prop shaft - a missing or wrongly ordered thrust washer is a common cause of noise that appears in gear. If the hardware checks out and the noise persists, send us a video and your serial number and we'll take it from there.

Check for an obstruction anywhere below the water pump, from the intakes up to the impeller. Also confirm the impeller wasn't damaged on the first fire-up - running with the intakes covered or without water will destroy a new impeller in seconds. If you've had an impeller fail previously, check the coolers and passages for debris, especially the power steering cooler.

The most common cause is the tub not being full enough. The lower unit has to be fully submerged so the water pump assembly itself is under water - partially submerged won't pick up. Two other things to check: if you pulled the top cover off the water pump and the impeller stayed in the cover, the impeller key will have dropped out of place; and on muffs, putting the boat in gear can shift the muffs just enough to stop the pickup, so squeeze them tighter in a vice and try again. A shifting issue has nothing to do with the water pump.

There are two. The port-side sensor runs to the trim pump and is the trim limit; the starboard sensor is the one your gauge runs off. If adjustment doesn't fix it, it's very common for the wiring to fail near the bellows - trace the wire back until it disappears into the boat. If you find a break, the correct repair is to replace both sensors as a pair.

There has to be play present to make U-joint noise, and the usual cause is the original clips being slightly undersized, which lets the caps spread once the drive runs under load. We have oversized U-joint clips and send them out at no charge. The fix is to remove the zerks, press the caps back together with a C-clamp and install 8 new oversized clips. Contact us with your upper unit serial number and we'll get them out to you.

If your anodes are in good condition and the corrosion is attacking the bearing carrier first, we'd question stray current or electrolysis nearby, particularly if the boat is kept in the water. It's worth having that measured while the boat is in its slip. Practical steps: disconnect the batteries or use a battery switch when charging in the water, pull the prop at the end of the season and touch up the paint, and keep the boat out of the water when you can. A gap opening up between the lower unit and the prop is not good - it causes cavitation and can slowly leak gear lube.

Yes, and we'll be straight with you about it: the issue traces back to the original Yamaha design, and we reproduced it when we remade the driveshaft. We've since corrected it going forward, and we developed an in-field repair collar so you don't have to replace the whole shaft - Yamaha treats the collar as part of the driveshaft and sells the complete shaft. More than a few Yamaha models are affected, not just one. We supply the repair collar free for our own units. Contact us with your serial number.

Often the engine coupler. A worn coupler will frequently work at low power and then slip once more power is applied, grabbing again when you slow down - which makes it feel intermittent. A useful check is to turn the engine over in gear and see whether the prop turns with it. If the drive shows no clunking, no metal in the lube and is pumping water, the coupler is the more likely suspect.

Yes, and we send these out at no charge even if the unit is out of warranty. That collar rides on the driveshaft under the water pump, right where the seals ride, and both our units and the OE units have been known to crack there. Our repair collar slides over the shaft and gets epoxied into place with any two-part epoxy rather than being pressed on like the original; leave it overnight to dry and reassemble with the new seals we send. Send us your serial number and shipping address.

If it's an SEI unit, we've made a repair collar specifically for this and we'll send it out at no cost along with new seals - just get us the serial numbers off the units. If it's an original Yamaha unit rather than one of ours, that collar is integral to the OE shaft and you'd need to go to Yamaha.

Very likely yes. Water getting past the bellows strips the grease out of the U-joints and the gimbal bearing, which is how a bellows problem turns into U-joint and bearing damage. Get a photo of the metal on the magnet and the condition of the joints, and check the bellows carefully before refitting anything.

Fitting a hydrofoil, including drilling the mounting holes in the plate, will not void the warranty by itself. What isn't covered is any damage caused by the installation or arising from it afterwards - if the fin is stood on and the case cracks, that failure is yours rather than ours.

Yes - fitting an aftermarket nose cone to our lower unit voids the warranty. If you need low water pickups, tell us which engine you're on: several of our units come with low and side water intakes as built, so you may not need to modify anything.

We cover paint under warranty once during the 3-year period. The touch-up process is the same as for any gearcase: light sanding, clean, zinc (green) primer, sand again, clean, then the top coat. Our units go out in black and can be painted any colour without affecting the warranty. Touching up paint is normal seasonal maintenance on any outdrive, particularly in salt water.

Write it on the outside of the box - that's all we need to match it up when it arrives. Box the unit up as securely as you can and send it to our Slovakia address.

No, we don't assemble the driveshaft into the Johnson/Evinrude lower units before shipping. It's a genuinely simple job though - line up the splines, tap it in with a rubber mallet and it clicks into place. If you get stuck, contact us and we'll talk you through it.

No - we only work on units that are still within the warranty period, meaning purchased in the last 3 years. For an older unit, a marine shop familiar with the OE drives can work on it (ours are built to the same design and OE parts fit), or a replacement unit is often the more economical route once labour is counted. We do sell the seal kits and water pump kits if you're doing the work yourself.

No. We manufacture and sell new aftermarket units, and the only repair work we do is our own warranty repairs. If you're looking to have an existing unit rebuilt, that's a job for a marine shop rather than for us - though in most cases a new unit from us works out comparable once the labour is counted.

We don't recommend particular shops, but anyone familiar with the original equipment drives can work on ours - they're built to the same design. One important caveat: if the unit is still under warranty, don't disassemble it beyond changing the water pump and gear lube, as that's what the warranty terms allow.

It's usually trapped air rather than a fault. An air bubble can work its way to the pump gears during shipping, since the boxes end up on every side. Remove the unit, lay it on its side with the pump portion at the lowest point and run it - that usually clears it. The units ship filled with ATF Dexron III, so top up with that if the level is low.

We use ATF, which has the advantage of showing up leaks clearly, though standard power trim fluid works just as well. To bleed it, keep the manual valve shut and cycle up, down, refill, and repeat - then check the final level with the unit trimmed all the way up. Only open the manual valve if you suspect trapped air remains based on the sound. When storing the boat for any length of time, leave the unit trimmed down if you can.

It depends on the season. From October through May, turnaround is normally 3 to 5 business days once the unit is with us. From June through September - our busiest stretch - allow 5 to 7 business days. Either way we inspect it and then repair or replace. A good approach is to pull the unit in the autumn and send it in then, when we're quickest and you're not missing the water.

With any water intrusion complaint we want the unit back so we can inspect everything internally for pitting and rust - water that's been in there does damage beyond the seal that let it in. Disassembly by anyone other than our own technicians voids the warranty, so replacing the seals yourself would end your cover. Contact us and we'll open a claim.

Please don't while it's under warranty. We need to be the only ones who open these units up, unless we've specifically approved otherwise, which is rare. Disassembling it yourself can jeopardise the claim. Changing the water pump and gear lube is fine - going further than that isn't. Contact us first and we'll tell you what to check.

No - a pressure test is a request rather than a requirement. It's genuinely helpful because it confirms the leak and where you believe it's coming from, which helps our inspection line up with your findings. If you don't have a tester available, go ahead and open the claim anyway.

No - the warranty covers the unit, not labour, and all repairs are done in-house at our Slovakia facility rather than by a local shop. We also don't do walk-in warranty exchanges: the unit comes in, we inspect it, and we repair or replace it. Allow 5 to 7 business days from receipt through the summer (June to September) and 3 to 5 the rest of the year. You pay the shipping to us and we cover the return leg.

You just need the serial number off the red tag on your SEI unit - no proof of purchase required for serialized units. Email info@seimarine.eu or contact us and we'll look it up and walk you through next steps.

Email info@seimarine.eu with the serial number off the lower unit, a description of what's being experienced, and photos - including the magnetic drain plug and the drained gear lube if metal is the concern. You can also contact us by phone. We'll issue a claim number and instructions; the unit then comes to our Slovakia facility for evaluation and we either repair or replace it.

Box it up as securely as you can - a sturdy moving box that's long enough to accommodate the driveshaft works well. Write your claim or RMA number on the outside of the box so we know what it is when it arrives.

If you ordered through seimarine.eu, your claim is handled by our European team regardless of where in Europe you're located, so the unit stays within Europe rather than crossing the Atlantic. If you ordered from our US operation at sterndrive.cc, claims go back to our Florida facility instead - contact whichever team you originally ordered from to open the claim.

Yes - a bent prop shaft would be covered under our no-fault warranty, as long as the unit isn't being used for commercial purposes. Get the serial number off the unit and contact us so we can open a claim and tell you what to send in.

It isn't a one-time warranty - claims are handled case by case across the 3 years. The one exception is paint and finish, which we cover once during the warranty period. What does end a claim is the unit having been opened by someone else; we can't warranty another technician's work.

Remove the water pump, the shift rod and the upper driveshaft, along with any prop hardware and anodes - those are yours and we don't need them. Submit the claim first and we'll send you the full instructions along with your claim number. Box it up as securely as you can and write the claim or RMA number on the outside.

It means we cover the failure regardless of cause - if the unit was run without gear lube, or run into rocks, that's still covered. The exclusions are commercial use, tournament fishing, boat rentals and competitive activity, and the unit being opened by someone other than us. That's a meaningfully broader cover than a standard manufacturer's defect warranty, and it runs 3 years from the date the unit ships.

You're responsible for the shipping to get the unit to us, and we cover the return shipping back to you. Once it arrives, turnaround is 5 to 7 business days through the summer (June to September) and 3 to 5 the rest of the year, and we either repair or replace it.

Yes, if you open the gearcase to do it. Opening the unit for anything beyond normal maintenance - the water pump and gear lube are fine - is the quickest way to void the warranty, and it's set out in our warranty policy. We know shipping a unit back is inconvenient in season, but we require the unit to come to us for evaluation and repair. Contact us first; sometimes the fix is a drain plug gasket or a water pump base, which you can do without affecting cover.

No - our warranty policy is that we need to see and inspect the failed drive first. Turnaround is normally 3 to 5 business days from when it arrives, and after that we either repair it or replace it depending on the failure. Factor the shipping each way into your timeline if you're working to a launch date.

No. Complete drives and lower units carry the 3-year fault-free warranty, while individual parts - a driveshaft or a bearing carrier, for example - carry a 1-year limited manufacturer's warranty. Trim and tilt systems are also 1 year. So the cover depends on what you bought, not just who made it.

On a replacement gearcase, the original manufacturer typically offers a 1-year warranty. We offer a 3-year no-fault warranty, which covers failures from customer damage through to manufacturing defects, provided the unit isn't used commercially, competitively or in a rental fleet. Rubber seals can fail from any manufacturer for a number of reasons - the difference is what's covered when they do.

SEI drives and lower units carry a 3-year fault-free warranty from the date of original purchase, and it's transferable - it stays with the unit. (Trim/tilt systems carry a separate 1-year warranty.) It covers manufacturing issues but excludes commercial use, tournament fishing, and racing.

No - we go back to the original purchase date, and the warranty is 3 years from that date. So if a unit bought in 2018 was warrantied and replaced in 2020, the clock still runs from 2018 and the replacement isn't covered for a fresh 3 years. The warranty does transfer with the unit if the boat is sold.

It's a 3-year fault-free warranty provided the unit isn't used for commercial use, tournament fishing, competitive activity or boat rentals. Charter fishing and rental fleets fall outside it. Within those terms it covers manufacturing issues, and it's attached to the drive before it leaves us, so there's no card to send in.

Three years, fault-free, from the date of original purchase - provided it isn't used for commercial, rental or competitive activity. That's the same warranty across our lower unit range. The units are made at our factory in Taiwan.

Trim and tilt systems carry a 1-year limited warranty, which is separate from the 3-year fault-free warranty on drives and lower units. Trim cylinders are also 1 year. The serial number on a trim unit is on a silver label, starting with the letter "A" followed by a 3 or 4 digit number - you'll need that to open a claim.

It starts the day the unit ships from our warehouse, and it runs 3 years from that date. There's nothing to register - the warranty is attached to the serial number before it leaves us, and any card in the box is just for your records. Note that it runs from that original date even if you bought through a dealer, and it doesn't reset if we replace the unit under a claim.

No - the warranty is attached to the drive before it leaves us, so there's nothing to register. Any card in the box is just for your own records. If you ever need to open a claim, the serial number off the unit is what we'll ask for.

Yes, and there's nothing to fill in on our end. Just make sure the new owner has the serial numbers off the unit - we track warranty by those numbers, so whoever holds them can open a claim for the remainder of the 3 years.

Yes - send us the 6-digit serial from the red tag and we can look up when it was sold and confirm the ratio it was built with. For context on age, the manufacturer is currently shipping drives in the 300,000-plus serial range, so a five-digit number is a genuinely old unit. Records for the oldest units are held separately, so those can take our warranty team a day to retrieve.

SEI has sold more than 300,000 units over the years, and has been in business since 2004. SEI Marine Europe opened in 2024 to bring that same manufacturing, warranty and support directly to European customers. Any mechanical device will have some failures across that volume, which is worth bearing in mind when reading mixed reviews online - it's also why we back them with a 3-year fault-free warranty and free technical support.

We're SEI - we manufacture these units, so everyone else who sells them gets them from us. seimarine.eu is SEI's own European operation, priced in euros, not a third-party reseller. Our US operation at sterndrive.cc is priced in US dollars for customers in North America and elsewhere outside Europe.

We don't currently have widely stocked distributors across Europe, so the quickest and most reliable route is to order directly from seimarine.eu, where you'll see delivery estimates and pricing at checkout. In-stock items ordered during business hours usually ship within a business day from our Považská Bystrica warehouse.

Create an account on seimarine.eu and follow the dealer sign-up flow during account setup. If you're mid-job you don't have to wait on that - you can order without a dealer account and get the application processed in parallel.

There's a minimum order value, and orders above a set threshold ship at no charge - dealer terms differ from retail, so contact us for your account's current figures. The exception either way is large items such as lower units and transom assemblies, which are priced by their size and weight.

None of our European dealers currently hold stock - the quickest and simplest route is to order directly from seimarine.eu, or contact us and we can take it directly. In-stock items ordered during business hours usually ship within a business day.

Yes. SEI Marine Europe operates at seimarine.eu, priced in euros, supplying customers across Europe from our warehouse in Považská Bystrica, Slovakia, and handling European warranty claims locally. Our original facility in Oldsmar, Florida, manufactures and ships units to the rest of the world, including North America. If you're not sure which applies to you, contact us and we'll point you to the right one.

SEI Marine Europe is located at Robotnícka 389, 017 01 Považská Bystrica, Slovakia. We're open 7:00 AM-2:00 PM local time on business days. Contact us by phone at +421 905 200 022 or by email at info@seimarine.eu.

We're at Robotnícka 389, 017 01 Považská Bystrica, Slovakia. Everything for the European market ships from here, and you're welcome to collect in person if you're local. Contact us at +421 905 200 022, 7:00 AM-2:00 PM local time on business days.

Our units are assembled in our own factory in Taiwan and distributed from our facilities in Slovakia (for Europe) and Florida (for the rest of the world). They're built to be as strong as or stronger than the original equipment, which is verified through testing at a private test lake in Florida. Worth noting that when you disassemble as many OE gearcases as we do, you find they're largely built from overseas-sourced parts too, even when final assembly happens domestically.

We manufacture outboard lower units, sterndrives and the related parts - gearcases, transom assemblies, trim and tilt systems, seals, water pumps, bearings and tooling for those applications. We don't make parts for other kinds of engines or vehicles, so if a part number looks similar but is from another machine entirely, it won't cross over. Tell us the engine you're working on and we'll tell you honestly whether it's something we cover.

Everything we manufacture is inspected to be an accurate reproduction, right down to X-ray inspection to confirm the materials match the OEM material. Every unit is built, pressure tested and manually shift-checked before it ships. Our drives were designed around the OEM drives and then tested against them on our own research lake.

We don't find that to be the case. We test our units against the OEM units, most of the time to the point of failure, and we spend hundreds of hours doing it at our test lake. A brand new unit is louder than a worn-in one until the gears bed together, which is what most people are hearing in the first few hours - it should quiet down after proper break-in.

We're happy to try. Contact us and let us know which language works best for you, and we'll do our best to help in it.