stuck Alpha One lower unit

I finally got it apart. The entire exhaust cavity between upper and lower was a mouse nest and there was dead grass and some cotton type fluff as the main mix of the mouse next.

The stud closest the transom had white powder around it and I am thinking that stud was binding in the hole it has to come out of.

I chipped a piece of the mating surface while I was trying to hammer in a cold chisel as a wedge. I was not prying. (Pisses me off).
 
Congratulations! You can use some JBWeld or MarineTex to fill that chip.

Mouse Nest! The little biters can about pour themselves into where they want to go. Thickness of a nickel or something if I recall. Good you got it out of there.
 
That white powder is probably salt build up. If you got a big build up on the rear main bearing of your engine, it would freeze up the whole engine. It's that tuff a stuff. It get's into the 5/8" seal of a hydraulic ram and it will freeze a hydraulic ram with 10's of thousands of PSI.
 
It was never run in salt water. Not even brackish. It was normally on the Hudson at Hyde Park, which is pretty far up. Never went very far down the river.
 
How long has it sat?

I once had to do some work on a volvo OD that, curiously, was moored at bruce's old marina. Each house had it's prerequisite boat.

The water pick on the drive has a cavity behind slits on the leading edge of the lower drive. I found in this cavity, a 2 1/2" oyster. It could only have implanted itself as a one cell 'baby' oyster. How long do you think that boat had to sit as this one cell oyster grew to 2 1/2 ". Lots of thins can happen if left undisturbed.
 
Its been a two years since it was in the water. But longer since the lower unit was off. I brought it to RAPP propeller in Albany (to have the skeg fixed) and he agreed that it was the stud closest to the transom (leading) that had white powder on it and was due to not pulling the lower unit ever other year.
 
I am SOOO glad the problem was the stud and not the input shaft spline from the lower rusted stuck into the output spline of the upper. I've seen outboards where the driveshaft was so stuck in the crankshaft that the intermediate housing had to be busted in pieces to access the stuck area. The OB's I'm referring to were OMC JohnRude's. They were meant to have grease up there and an O-Ring on the driveshaft (not propeller shaft!) to keep water from spinning up and washing that grease out. The there was the case where the internal spline in the bottom of the crankshaft was so worn that it couldn't turn the driveshaft...
 
Is the lube totally contained in the lower unit and there is no vent hose or anything to the upper unit?
 
On the starboard side of the upper and lower, there's a transfer tube that allows drive fluid to travel throughout the drive. There is what is called a QUAD ring. It's just 4 skinny O-rings fused together. Put a teeny tiny bit of silicone or even grease to hold this quad ring in place when assembling. If the quad ring moves or falls out, the whole drive will be contaminated with water and will either seize or break gears.
 
There is an o-ring near the top of the input shaft that goes into the upper unit. I have read to not use that o-ring. I think it was because you will never get it right when putting it back together. But what keeps water out of that spline area on the top of the drive shaft?
 
The earlier drives had a groove cut into the top of the drive shaft to keep it positioned. If there's not groove, don't bother with the Oring.

Been a while since I've done the top end, but, logic would dictate a seal for the top of the drive shaft.

Merc has done some pretty funny sh*t over the years...but I guess it works. The driven gear that the drive shaft mates to used to be an all solid gear. Later gears have a hole that runs from the spline side up thru the gear to the top gear cavity. Never struck me as being sound engineering.
 
Maybe they weren't getting enuff failure in the upper. The upper bevel gears are the heaviest duty in the whole drive.
 
a 3/8ths or 7/16ths open end wrench fits nicely on each side to act as a spacer to force the unit apart.
 
quote:
Originally posted by jtybt15

On the starboard side of the upper and lower, there's a transfer tube that allows drive fluid to travel throughout the drive. There is what is called a QUAD ring. It's just 4 skinny O-rings fused together. Put a teeny tiny bit of silicone or even grease to hold this quad ring in place when assembling. If the quad ring moves or falls out, the whole drive will be contaminated with water and will either seize or break gears.

Click to expand...


I assume the seal is part #26-45577 1.

Anything special about the 5 nuts that hold the lower housing to the upper. Just SS with nylon lock?
 
I don't have a parts book to ID that part #. The quad ring is about 5/16" in diameter and is extremely important to replace correctly
 
The locking nuts that hold on the lower unit. Are they just normal fine thread SS locking nylon nuts? (Actually I suppose that not a normal nut).

Can I get ones at hardware store or do I need Mercruiser ones? I do not believe there are grades of SS nuts like there is for normal nuts (grade 5, etc).
 
For Gen-II the quad ring is 45577. The water pump kit includes one, but I bought a couple extras.
 
Any SS nylok nuts will work...unless they're already rusty.
 
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