9.9 Johnson LS _ Oil from exhaust

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Steve Hall

I have an old 9.9 outboard and when I run it for a few minutes and turn it off, some oil comes out the foot exhaust. Is this too much oil in the fuel, or is it some kind of oil blow-by from the cylinders? Steve Hall S/V Helen Highwater
 
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Ray Bowles

Steve, It is probably unburned oil from your

gas/oil mixture. If you are only running your engine for a few minutes you don't get it up to operating tempreture and therefore you will have incomplete combustion. It takes a good 15 minutes at better than 1/2 throttle to warm the engine up enough to get clean combustion. Keeping the engine tuned up with a proper carb setting is very important. Using a sparkplug with a higher heat range will also help if you don't run your motor very long at any time. One outcome of running in short times is plug fouling which is no big deal if you have spare plugs. Another is smoking and gas/oil puddles and slicks behind your boat and that is a problem. Using a GOOD brand oil will also help. Changing your oil ratio is not something you should do unless you know how to read plugs and know how to set air/fuel ratios. Hope this helps. Ray S/V Speedy
 
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Steve Hall

1984 9.9 Johnson LS

That is the exact same model that I have. I can't believe that comes out of that exhaust! I read that four strokes don't have that problem. Steve Hall S/V Helen Highwater
 
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