Lower end oil leak

[Derric]

Used my boat yesterday and when I put it up I let the engine down to let all the water run out of it. I found a little puddle of brown sludge coming out of the prop. I took the prop off and sprayed WD-40 down in the cavity cause it was greasy and dirty inside there. Do I have a seal out inside the lower unit?

 

[TriadSteeler]

Re: Lower end oil leak

I just dealt with this issue. It could be one of two things. 1) Lower unit lube mixing with the coolant flow. or 2) uncombusted fuel in the exhaust mixing with the coolant exhaust.

Uncombusted fuel is common.

1) smell the sludge. Is it pungent, that will tell you if it is LU lube. or does it smell like gas/2-cyc mix, uncombusted fuel.
2)I would suggest draining the lower unit specifically checking for water mixed with the lube.
3) I would also perform a vacuum and pressure check on the lower unit. (Do a search on this forum for vacuum test. There are several threads that tell you how to perform the test, what pressures to use, etc)

If the the lube contains no water it is likely that you don't have a vacuum leak at least.

The pressure/vac test will tell you conclusively if the lower unit seals need replacing. If both check out ok, then it would be safe to assume that uncombusted fuel is the culprit of the brown sludge.

 

[Derric]

Re: Lower end oil leak

Changed the oil and it had no water in it. Think maybe from trolling all day and higher altitude just had alot unburned gas?

 

[MaggieRose]

Re: Lower end oil leak

Lighter air at higher altitude will definitely give you a richer mixture throughout the throttle range.