1987 Evinrude 150 Unburnt oil running down midsection

[BJess]

I have read on several older threads about multiple different things that could create the black oil substance running down the front of the midsection. It comes from under the lower cowling and you can see it is coming from under the the power head area but can't see exactly where it comes from. I am understanding that it is unburnt oil but I would think this should run out of the prop. The motor runs great and is worth a minor repair cost to me since I can't afford a new $10k motor. What does anyone think can be done and how hard is it to do. I am relatively mechanical and have replaced pretty much all of the electrical components, epoxied new magnets on the flywheel, new water pump assembly, etc. so to do the work myself is an option.

Thank you!

 

[Bosunsmate]

Re: 1987 Evinrude 150 Unburnt oil running down midsection

hows the plugs look?
one or more might not be firing
It might be a failing powerhead to adaptor plate gasket.

 

[Will Bark]

Re: 1987 Evinrude 150 Unburnt oil running down midsection

My 87 150 is doing the same thing and it is probably the gasket but I can't afford to have the powerhead removed and replaced so I will just live with motor operation is not a problem.

 

[Blazinmonkey]

Re: 1987 Evinrude 150 Unburnt oil running down midsection

I attached pics of my 1983 150 cross-flow...
you can see oil down the midsection & prop.
this mainly happens when i flush the motor on the `ear muffs'
I boat in salt water so when I get home I idle with water then salt away.
after a few hours the oil appears. now if get home & I let the boat sit for a few hours before flushing the oil is not as evident. I think that is because I am only idling for a moment before loading...

 

[BJess]

Re: 1987 Evinrude 150 Unburnt oil running down midsection

hows the plugs look?
one or more might not be firing
It might be a failing powerhead to adaptor plate gasket.

Sorry guys. I asked a question and then disappeared. I had a very busy few days at work. The plugs look good and the motor runs very crisp. We put a spark tester on it after changing the stator to ensure all 6 were firing. How hard is that base gasket to change?

 

[BJess]

Re: 1987 Evinrude 150 Unburnt oil running down midsection

I attached pics of my 1983 150 cross-flow...
you can see oil down the midsection & prop.
this mainly happens when i flush the motor on the `ear muffs'
I boat in salt water so when I get home I idle with water then salt away.
after a few hours the oil appears. now if get home & I let the boat sit for a few hours before flushing the oil is not as evident. I think that is because I am only idling for a moment before loading...View attachment 217325View attachment 217326View attachment 217327View attachment 217328View attachment 217329

My situation is very similar to the photos BlazinMonkey put up here. It is definitely black oil just like that.

 

[emdsapmgr]

Re: 1987 Evinrude 150 Unburnt oil running down midsection

If it's running down the midsection, it's probably the power head base gasket. Unusual for it to fail on the V6 engines (mostly a V4 problem) but it's not unheard of. You have to lift the powerhead up about 12" to put on the new gasket. About a 3 hour job. It's not going to cause an imminent failure the way it is-just awfully messy. The only real problem I see is that with the oil leak comes exhaust smoke leakage-which will fill the inside of the cowling. Once that happens, the engine will suck that smoke back into the carbs when running. That's not really a good thing on a long-term basis.