Help Please - 1974 Evinrude 85 HP

[evinrudehelpplease]

Ok, we just picked up a boat with a 1974 Evinrude 85 HP outboard.

Problem is it looks to be oil fouled up. No idea why. It will run great for about 45 min (with new plugs) but then it fouls.

Pulled the plugs and they are black with oil and excessive fuel.

HELP ME PLEASE!!

Thanks

 

[divinginn]

Re: Help Please - 1974 Evinrude 85 HP

Dirty carbs can cause that problem,I went through 3 sets of plugs on mine until I got the carbs right, then no more problems for now.

 

[ezeke]

Re: Help Please - 1974 Evinrude 85 HP

Other things that will help:

Make sure that the engine is running at the correct temperature and that you have a good thermostat (vernatherm).

Use synthetic or synthetic blend TC-W3 oil.

Use Champion QL77JC4 plugs gapped at .030.

Check that the automatic choke has been disabled.

Add Carbon Guard to your fuel.

 

[evinrudehelpplease]

Re: Help Please - 1974 Evinrude 85 HP

I just spoke to one guy, who said it might be the coils or coil pack?

Any idea there? It's got good compression 120/120/115/110.

Thanks

 

[mrracer98]

Re: Help Please - 1974 Evinrude 85 HP

1+ on cleaning the carbs.. These motors are the best motors that run with a fouled cylinder that I have ever seen.. Needs a carb cleaning man... sorry, and I use sea foam EVERY OZ OF GAS THAT RUNS THOUGH THESE MOTORS... they can carbon up bad