BOAT = Break Out Another Thousand

THere we were, humming down the lake at 58mph, playing with the trim to get that last 2mph out of her, turning 4300rpms, when we got a vibration and loss of proplusion, followed by overheating. Something is gone in the outdrive between the engine and the prop. Lower unit engages gears in fwd and reverse, but is not locking up against motor compression. Think I feel the resistance of the water impeller and hear a rubber squeak. Probably the bevel gears in the upper unit...

Sure was nice while it lasted...

Charlie, does that beast have the 460 Berkeley jet?

That sounds like a Volvo drive, Upper bevel failure is common on them.

Mine is just a lowly little clamp on motor, Pic taken a few days ago in my front yard, My wife calls this shot, "Motorhead"

84 Mercruiser Alpha1, 350 chevy with about +.2 over stock compression and a CompCams XM256H cam, stock 260hp, probably about 280 or so as built, maybe more depending on how good the ring seal we got is.

Well within the rating for the drive, did it run low on oil? I hear of input bearing failures on those drives, be nice if that went and the gears survived? Not sure they do that.
I run Redline Shockproof oil with the gears. In my Yamaha outboard you can barely hear or feel it shift.

Took off the outdrive this afternoon (I'm getting way too good at that - 18 minutes from stop the truck to get out the tools until it was off in two pieces).

Lower unit engages F and R and locks in, vertical driveshaft rotates smooth and fine.

Upper unit ujoint shaft turns smooth, but the internal splines in the driven gear do not turn. I don't have the measuring tools or the special spanner to take the upper apart and put it back together - dropped it off at Bolton Marine at 5:00 today for them to take it apart for me in the a.m. Either the lower bearing on the driven gear is gone, or the teeth are gone on the drive or driven gear. We'll see...

Do you use straight Redline or mixed with outdrive lube?

I've been told that 300ftlbs is the safe limit on an Alpha1, but I've never seen a factory rating. I know the SeaRay white Alpha1 had a 454 in front of it, and I'm sure that hog had over 300ftlbs at 4600rpms. I've never seen a black Alpha1 with more than the stock MCruiser 260hp on it.

Yes, straight Redline Lightweight Shockproof. The lightweight is about a 75W gearoil. There is thicker and thinner versions as well.
Does your upper gear case have the remote oil reservoir?

Out drive oils are essentially just GL5 90W mineral oil, nothing special.