181 oil leak under intake??

[merc84]

I have a 1984 Merccruiser 140 (181cid). It has an oil leak.. the oil is showing under the intake manifold. It has been leaking for a few seasons... first it was dark oil.. and very little... however it seems to be getting worse... I now have fresh oil under the intake after an outing. Not sure where it is comming from... I don't suspect the intake has oil going through it... but possibly the head gasket... ???

What gaskets should I replace?

Thx

 

[Bondo]

Re: 181 oil leak under intake??

Ayuh,...

You'll have to narrow it down to Exactly Where it's leaking,...

Generally speaking,...
That side of the motor doesn't have Oil in it,... That's the Water side of the block...

My best Guess is,..
It's either running down from the valve cover, or the draft tube....

 

[chiefalen]

Re: 181 oil leak under intake??

25 year old motor, bet never been out of the boat. Nows the time to pull it if it was mine. I would do a compression check first after running it 15 minutes.

Write the numbers down and post them.

Whats the oil look like after you run it with water going to the drive of course ?

I don't post this as a whim but fresh oil in the bilge ain't a good sign and good compression numbers would rule out a few things, and maybe, just maybe you can get away with just a fresh set of gaskets and a few seals.

My 85' 140 when i took it out of the donor boat needed a new pan. Lip was rotted thru and the timing cover bottom gasket was shot.

Nows the time to do it plenty time before the season starts and parts are still cheap ( wink ).

Need help with tips on how to pull it just ask everyone here would give them.

 

[merc84]

Re: 181 oil leak under intake??

I agree.. that side of the motor should not have oil... what I am seeing is some drops of oil hanging under the intake.. at first (couple years ago) it was dark black oil.. probably cause I didn't notice it for awhile... now it looks like fresh oil. I suspect is either a valve cover gasket.. or possibly the head gasket... The boat still runs good.. still hits WOT and good speed... no other leaks seen.. no oil in the bilge and no water in the oil.

The boat lived it's life in the midwest (mississippi river).. so was primarily a summer weekend boat.. probably has low hours. I've owned the boat for 16yrs.. only had to do a few minor repairs.. bellows, coil, carb rebuild, tune ups, fuel pump.

I hate to tear down the entire engine for such a small leak... guess I will start with a valve cover gasket and see what happens.