Black oily stuff-Johnson 35hp

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Black oily stuff-Johnson 35hp

Postby vernonfarmer » Sat Jul 06, 2013 2:13 pm

Hope someone can I.D. this issue for me....
'57 Johnson 35hp. Black oil stuff running down the side of the motor. Motor runs a little rough, sometimes seems to be on one cylinder and then back to two. Changed the coils and plug wires.
I wonder if the bottom engine seal is the culprit?

Image
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Re: Black oily stuff-Johnson 35hp

Postby JoeCB » Tue Jul 09, 2013 6:25 pm

I hope that we get an answer to this problem. I have the same issue with my 1957 Evinrude 35 hp, the same motor as your Johnson. I'll ask around some of the more knowlegable guys around these parts.

Joe B
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Re: Black oily stuff-Johnson 35hp

Postby LancerBoy » Wed Jul 10, 2013 3:26 am

Just unburnt fuel?????

ask at the forum of www.aomci.org

Andreas
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Re: Black oily stuff-Johnson 35hp

Postby JoeCB » Wed Jul 10, 2013 11:56 am

Burnt fuel? could be, but nothing should be comming out of that joint under the engine pan. I too suspect a lower crankshaft seal or cylinder to tower joint gasket, but don't have confirmation as yet.
Joe B
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Re: Black oily stuff-Johnson 35hp

Postby Torchie » Thu Jul 11, 2013 12:44 pm

Check your compression relief valves to make sure they are seating properly.
If not they will leak and this is the results.
Out the valves. Into the lower motor case and then down the exhaust leg.
Could also explain why sometimes it seems like it is running on 1 cylinder. Low compression on the cylinder that is not sealing.

You could do a compression test but if it is intermitent you may not catch it.
Hope this helps.
Torchie.
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Re: Black oily stuff-Johnson 35hp

Postby vernonfarmer » Fri Jul 12, 2013 5:24 pm

I like what you are selling, Torchie. I'm not near the motor. How does one check for proper seating and then make the fix?

John
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Re: Black oily stuff-Johnson 35hp

Postby Torchie » Fri Jul 12, 2013 6:35 pm

John.
A quick way is to do a compression test but as I said if it is intermitent you may not catch it. Or you may get a different number while doing multiple test on the same cylinder suggesting some times it seals and others it doesn't. But I have heard of cases where the engine continues to run well for a time. Plus do a visual inspection of the area and see if you can spot an oil trail.
Unfortunately, the best way is to remove the head and do a visual inspection as well as removing the valve and reinstalling it.
Some times carbon will get in there and cause the valve to not seat correctly. Also I believe that there is an O-ring seal on the stem of the valve it self. That could be worn out.
These valves don't really wear out like an intake or exhaust valve will because they only move when the starter or rope pull is engaged.
There is no external fix that I know of but I will go out to the shop tomorrow and pull the cover off mine and take a good look.
Karl.
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