3.0L AlphaG2 strange leak question

[PeterB26]

On the inside of the transom, at the very lowest part of the transom shield on the inside of the boat I have a slow seaping leak.

I mostly know it is there because of the streak of rust it creates.

I thought this might be a leaky u-joint bellows or attendant leaks into the u-joint bellows, with the water finding its way in through the gimbal bearing...but I have just resealed those parts and the leak persists. Furthermore there is no wetness, staining, or sign of water at any part above the absolute lowest part of the inside of the transom shield. Not on or around the drive shaft, not under it, not on top of the exhaust elbow...nowhere. Just a streak of rust from under the bitter-bottom of the transom shield.

So I am thinking that the leak may be where the exhaust ?elbow?... not to be confused with the exhaust riser, but rather the ?elbow? that exits the gimbal housing, may be the problem.

I can't find any reference to a gasket between the elbow and the gimbal hosing, It is not part of the engine microfisch exhaust parts diagram, which list the elbow, and it is not part of the gimbal housing diagram.

Anybody know where to look for a part number?
Has anyone had a similar leak?
Has anyone done this job and have advice?

Thanks

 

[Rick Stephens]

I can't think of anything that would be called an 'exhaust elbow' down there. The exhaust travels down the 'Y' pipe (even though it is not a Y on a 4 cylinder) - the Y pipe has a 90 degree bend at the bottom and directly connects to the gimbal housing with 4 bolts. There is a rubber exhaust pipe seal that goes in there. That is pretty much it. (part #41802 listed on the gimbal housing parts page)

Rick

 

[Rick Stephens]

Might just be the transom seal itself. Seeping in between the gimbal housing and the transom.

 

[PeterB26]

On the the 3.0L parts diagram Merc calls the "y pipe" an elbow because there is only one side to it. But you have the right thing.

Might just be the transom seal itself. Seeping in between the gimbal housing and the transom

This has occured to me and I am really hoping that it isn't so.

After some thought it might not be the exhaust because there is no exhaust leak into the engine box that I can identify when running.

 

[Fun Times]

Might just be the transom seal itself. Seeping in between the gimbal housing and the transom.

^ Or maybe loose bolt.

 

[PeterB26]

RE: the exhaust gasket part:

On the parts diagram for Alpha G2 s/n 0L100040 & up the part numbers offered are diferent... they are 8m0068607 (no tabs) and 8m0068609 (with tabs; no longer available) and they don't specifically say anything about exhaust. If you try to source either of those part numbers you get nothing.

But the earlier s/n drive parts diagrams do list 41802... and the earliest diagram does say exhaust gasket. So by missing it I was only half as lame as I thought I was! How foolish of me to loook up my parts by serieal number! LOL!

Fun Times:
Easy enough to take a turn on the bolts, Good advice. I'll be sure to give it a try. Lucky for me I have pretty darn good access back there when compared to some installations.

Peter