Oil build up under crowling on powerhead and spark plugs —1972 85hp Johnson

[Josh1972-85hp-Johnson]

I can’t seem to find online much about someone having the same problem. My engine has an back oil residue or possibly carbon build up starting to form on the powerhead and everywhere under the crowling. Was cleaned up and came back. I can post some pics later. It was very dirty under there from a friend that borrowed the boat last summer and mixed the oil 2.5times more rich (more oil) then it calls for. Suppose to be 50:1 ratio and he thought that meant 50ml of oil to 1litre of gas. That’s not how any ratio works, can’t be different units of measurements!!! Lol. Engine ran ok after that, little more rough maybe. Anyways I rebuilt the entire ignition system and lower unit with new seal kit this spring, replacing every part other than the points basically. While I was doing so I cleaned the entire engine very well with acetone and mineral spirits q-tips etc. It was almost perfectly clean other than down low where I couldn’t reach and the foam all in the crowling was still black.. didn’t know how to clean that. I only ran engine for a few hours after cleaning it and it was dirty again, part of new spark plugs showing were black not white and black build up on powerhead a bit and more down low in crowling especially. Was so bad before I cleaned it though there was even an oil film on inside of flywheel etc. So I’m wondering if it could be just oil spreading around from what’s left under the hood? Or do I have an exhaust leak through the exhaust gasket or powerhead gasket as some people were talking about. The engine runs great! Like new, so don’t think much exhaust is leaking or it would get into carb and choke it out with the CO2. I guess I should run it with the crowling off and look for exhaust etc. I was planning on cleaning engine by running some sea foam through it as I have heard good things. Maybe this will show white smoke coming out somewhere if there is a bad leak. Also hope it will clean engine up and get it running even better. I always mix oil perfect and also only have ever used premium gasoline. Any suggestions would help a lot!!! Thanks in advance.
Engine is model # 85ESL 72R
1972 85hp Johnson with Hydro-Electric-Shift

 

[jimmbo]

Are the oil recircuation lines hooked up and not cracked/broken?
A bit of Dawn Dish Soap and hot water, along with some perseverance should clean the foam in the engine cowl.

 

[Josh1972-85hp-Johnson]

Thanks for the reply. That’s a good idea for the crowl. I just didn’t think it was a big deal, but maybe best to not have excess oil in there. Corect me if I’m wrong but I don’t think my engine would have any oil recirculation lines because it’s a 2-stroke, but not oil injected. I have to premix the oil/ gas to 50:1.

 

[racerone]

Yes we know it is a 2 stroke !---And it has internal oil recirculation passages.-----Replace exhaust cover gaskets on back of the block.

 

[jimmbo]

All the recirc is internal? No hose/pipe from lower bearing?

 

[racerone]

That is what post # 4 indicates !---No external hoses/ pipes on those crossflow V-4 motors-----Jimmbo , have you rebuilt any V-4 motors ?

 

[jimmbo]

Not for a long time. About 25 yrs

 

[Josh1972-85hp-Johnson]

Apparently I don’t know anything about this part of the engine, what does the oil recirculation do in terms of engine function..?

 

[Josh1972-85hp-Johnson]

Also how big of a job is the exhaust cover gasket replacement? What all do you need to remove. I haven’t looked into the parts/ diagrams yet.