I need help with a leak

[MarioV]

I have a 4.3 OMC Cobra Out Drive That seems to be leaking water into the boat. The water comes from the rear of the engine where it meet the transom. the leak is minor maybe 2 or 3 gallons per hour but I feel it needs to get fixed. It appears as if there might be some sort of boot in that area that prevents water from entering. If so is that boot difficult to change?
If anybody can help I would appreciate it.

[superV]

That sounds like the problem (ex. bellow) and it is a common one. You need to fix right away 3-4 gallons per hour eek! If that thing fails you will be on the bottom in 3-4 min. Get it fixed ASAP and dont use it till then! frown

[MarioV]

Now that I know I need to fix the problem right away what are the possible causes of the leak and what are the possibilities of fixing the problem myself?

[gnarley]

Could be the bellows for the input shaft U-joints & leaking past the gimble bearing, either case it needs fixing ASAP. Check your drive bellows with the drive up, near the hose clamps you might find the clamp in the wrong position, which cut through the rubber. I don't think it's the exhaust, how would water get past the y-pipe or out the manifolds? You would have to have a leak inside the exhaust inside the boat as well & below the water line. Also check the seal around drive, it could also be leaking if loose or missing nuts & you need to check this while in the water by bending down & looking with a flashlight & mirror to see everything from inside!
YOU can fix it yourself if experienced & have tools & books, first you need to find the leak. If it’s not around the transom shield/adapter it must be a boot, hose or bellows. Then which one that’s leaking determines the fix & most all require the drive come off & if it hasn't for a while it should anyway for U-joint service. If you can't do it, it will cost around $500 or so if no other damage has been done due to water in the transom or other unexpected problems. Just make sure that when it goes back together the engine is lined up correctly for the input shaft to line up! Or more damage may occur
Good luck
[ March 10, 2003, 01:44 PM: Message edited by: gnarley ]

[DUCKY]

gnarley:
Could be the bellows for the input shaft U-joints & leaking past the gimble bearing, either case it needs fixing ASAP. Check your drive bellows with the drive up, near the hose clamps you might find the clamp in the wrong position, which cut through the rubber. I don't think it's the exhaust, how would water get past the y-pipe or out the manifolds? You would have to have a leak inside the exhaust inside the boat as well & below the water line. Also check the seal around drive, it could also be leaking if loose or missing nuts & you need to check this while in the water by bending down & looking with a flashlight & mirror to see everything from inside!
YOU can fix it yourself if experienced & have tools & books, first you need to find the leak. If it’s not around the transom shield/adapter it must be a boot, hose or bellows. Then which one that’s leaking determines the fix & most all require the drive come off & if it hasn't for a while it should anyway for U-joint service. If you can't do it, it will cost around $500 or so if no other damage has been done due to water in the transom or other unexpected problems. Just make sure that when it goes back together the engine is lined up correctly for the input shaft to line up! Or more damage may occur
Good luck That pretty much covers it, but probably more like $500 for labor plus another $250 plus for parts. The two bellows and gimble bearing alone list for around $150, plus any other needed parts such as hoses, gaskets, gear oil, etc.... If it's apart that far, you should have all three bellows (u-joint, exhaust, shift cable), the gimbal bearing, and probably the u-joints replaced. It's cheap insurance.

[MarioV]

Superv, gnarly, ducky
Thank you all for your postings now its time to get to work. I'll check those things out and post my results.