Outdrive is just the other name boaters use for a sterndrive, the drive unit that hangs off the transom and turns engine power into prop thrust. A rebuild takes it fully apart, replaces the bearings and seals, checks the gearset, and puts it back together shimmed and tested. Brad rebuilds outdrives from all three major families: MerCruiser, Volvo Penta and OMC Cobra. Mail it in from anywhere or drop it off in Central New York.
Signs an outdrive is due for a rebuild
- Gear oil that comes out gray or with water in it
- A noise from the drive that rises and falls with rpm
- Vibration at cruise that was not there last season
- Stiff or notchy shifting, or a drive that pops out of gear
- Rust weeping from a seal seam or the driveshaft area
- Prop that wobbles or a driveshaft with felt play
What Brad checks on an outdrive
- Air pressure test to confirm the drive holds a seal
- Vacuum test to catch leaks that only show under suction
- Read the drain oil for water and metal content
- Spin the bearings by hand for roughness and drag
- Check gear backlash and the tooth contact pattern
- Inspect the transom seals and bellows where the drive mates
The fix and what to expect
The outdrive comes apart to the bare housings. Upper and lower bearings, the driveshaft and prop shaft seals, o-rings and the water pump all get renewed. Worn gears or a rounded clutch dog get replaced, then the unit is shimmed to the correct gear pattern and pressure tested. Expect a written list of what was worn and a drive that runs quiet and dry. Most outdrives turn around in one to two weeks once they land on the bench.
Alpha, Bravo, SX and Cobra rebuild differently
Not every outdrive rebuilds the same way. The MerCruiser Alpha One is a lighter drive with a water pump up in the drive itself, so the pump and the shift shaft seal get attention every time. The Bravo carries its water pump on the engine and runs a bigger gearset for higher horsepower, so bearing preload matters more. The Volvo Penta SX and OMC Cobra use their own shift and cooling designs, and Cobra drives in particular need the cooling passages and shift cable checked. Brad has the tooling and the shim stock for all of them.