Bearing Carrier
Do your Yamaha lower units have a water-cooled bearing carrier?
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.
Does the MerCruiser bearing carrier come with the bearing and seals fitted?
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.
Does the Yamaha driveshaft bearing housing come with the bearing and seals?
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.
Does the bearing carrier come with the large O-ring?
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.
Does the bearing carrier come with the seals and bearings installed?
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.
Corrosion Protection
What corrosion protection do your drives have?
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.
Driveshaft
Can I move the driveshaft from my old lower unit into a new SEI unit?
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.
Can I use an SEI driveshaft in an original OEM gearcase?
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.
Do I need a new upper driveshaft with the SE306?
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.
Finish
Your lower unit is black but my engine is silver - can I repaint it?
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.
Gear Lube
Does the unit come filled with gear oil?
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.
Gear Set
What's included in a complete gear set?
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.
Hardware
Is the hardware in your installation kits stainless steel?
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.
Install Kit
Do I really need the installation kit?
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.
What comes in the installation kit, and do I need it?
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.
What's actually in the installation kit and where does each part go?
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.
Which bolts come in the installation kit?
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.
Oil System
Does your SE116 drive work with the remote gear lube bottle?
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.
Parts
Do you sell individual internal parts for your own drives?
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.
Do you sell individual parts for Suzuki lower units?
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.
Prop Hub
Which prop hub kit do I need with my new Mercury lower unit?
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.
Quality
Are the gears in your lower units hardened?
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.
Seals
Can I use Yamaha OEM seals in an SEI lower unit?
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.
Do I need a seal kit to join the upper and lower halves of my drive?
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.
Is there a gasket between the upper and lower halves of an SE106?
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.
What gaskets do I need to change a Cobra lower unit?
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.
Shift Shaft
Does the SE205 come with the extra-long (25") shift shaft?
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.
Skeg Guard
Does the drive come with a skeg guard?
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.
Thrust Washer
Do I need a different thrust washer with my new lower unit?
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.
I'm running an aftermarket prop - will your thrust washer fit?
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.
My prop's splined washer won't grab on the new Yamaha lower - is the taper different?
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.
Which thrust washer do I need with an OMC lower unit?
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.
Transom Assembly
Do SEI transom assemblies use OEM MerCruiser parts?
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.
Is the Bravo transom assembly complete?
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.
What comes with a Bravo transom assembly?
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.
Trim
Do your trim and tilt units come filled with fluid and tested?
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.
Water Intake
Do your SE216 units have low water pickups?
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.
Water Pump
Can I use an OEM water pump kit on an SEI lower 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.
Do I need an SEI-specific water pump for my Yamaha lower unit?
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.
Do impeller kits come with instructions?
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, call or text us at 813-925-7127 and we'll talk you through the order the parts go in.
Does the lower unit come with a new water pump?
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.
Does the lower unit come with the water pump installed?
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.
How do I find which water pump kit fits my older Johnson or Evinrude?
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.
What'S Included
Can I reuse the upper driveshaft from my old gearcase?
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.
Do I need to transfer the shift shaft and upper driveshaft to the new unit?
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.
Do your lower units come with installation instructions?
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.
Does the Bravo Three lower unit need an installation kit?
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.
Does the OMC Cobra lower come with mounting hardware?
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.
Does the OMC lower unit come with a new retaining clip?
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.
Does the SE306 have a speedometer pickup in the front of the unit?
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.
Does the complete Bravo drive arrive assembled?
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.
Does the complete Yamaha lower include the exhaust damper seal and trim tab anode?
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.
Is the Mercury lower unit complete and ready to install?
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.
Is the unit ready to bolt on out of the box?
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.
My Gen II lower says a speedometer fitting is required - what is that?
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.
My new drive arrived with no mounting hardware - is that right?
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.
What can I reuse from my old gearcase with the SE306-C?
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.
What comes with a Yamaha complete lower unit?
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.
What else do I need to buy alongside a Johnson or Evinrude lower unit?
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.
What is NOT included with a Johnson/Evinrude lower unit?
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.