Lots of Oil in Bellows

[MTBoat]

At the end of last season, I experienced the engine running at usual RPMs, but, the speed slowing, and after a few miles (I had to get back to shore) and a trip to test it, it got much worse and I quit using it. II thought maybe the coupler was going bad, however, I did not experience overheating or any strange smell.

This season, I pulled the Alpha One Gen One outdrive off and there was lots of oil in the bellows, outdrive oil I assume.

I reached inside and it seems my new gimble bearing is no worse for wear. I intend to check the engine alignment as it was not done last time they put the outdrive on (top mechanic said he usually never needs to).

My questions:

1. As a relative newbie at overhauling these things, does it appear that I will have to pull the engine and examine the coupler, or is there another way?
2. And/or is it most likely all in the lower unit and can anyone explain most likely what is happening, where's the slippage etc?
3. What's the next logical and least expensive step?

Thanks

 

[AzFisherman84]

Re: Lots of Oil in Bellows

I just finished doing I similar repair after find a large amount of gear oil in my bellows. So my suggestion would be to re-seal your upper unit first (I believe the total cost to do this repair was around 230 or so); you will need some special tool which are a spanner wrench part # 91-17256 ($65) used to remove the retainer nut from around the yoke assembly and seal driver part # 91-43591T ($27) to help with removal and install of the oil seal. The seal kit from mercruiser dealer was 55 and I replaced the back yoke assembly lead in the drive because the old one had a small groove which contributed to the problem. Yoke assemebly was 80 from west marine online store.

Here is the thread I used to help me through the repair, http://forums.iboats.com/showthread.php?t=545329&highlight=1970+upper+unit+seal

also mercstuff.com; http://www.mercstuff.com/yokesealreplacement.htm

will also help you through the repair. I hope this info is helpful.

 

[IanFS]

Re: Lots of Oil in Bellows

Seconded, it sounds as if you have oil leaking into the bellows from your drive oil seal. I also have some pictures I took when I replaced my top seal..........
This is the assembly in bits

The new seals are fairly easy to remove with a screwdriver and hammer.....gently and fit with a soft hammer or mallet, they are a tolerance fit...

The interesting bit was torquing the assembly to 6in lbs, not many torque wrenches in the UK go this low, so a little inginuity was required. An old set of butchers scales dating back to the late 1800's which my grnafather used still reasonably accurate when I calibrated them with a pound of weights tested on a brand new electronic scales.



Then finally found 6" from a socket and wrench to make 6" lbs of torque....


Your secondary slippage problem might be your prop rather than your coupler, it may well be slipping on the torque hub. I would check that first.

 

[abrx7]

Re: Lots of Oil in Bellows

I got my parts from http://bpi.ebasicpower.com/index.php

I did this same job last year. input shaft seal and a new yoke.

 

[MTBoat]

Re: Lots of Oil in Bellows

Thanks, I appreciate all of the excellent input and advice, and photos and links.
Upon inspection of the prop, which I felt may be spun, I found a downrigger wire ball that was lodged inside where the prop meets the housing and had effectively shaved of an amount on the inner diameter of the prop, probably letting exhaust escape and create cavitation. Replaced with different prop and will test.
The upper unit surely needs seal and yoke as prescribed. I do not think the coupler was spun so will test soon and see if theories are reality.