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 Gas smell in engine oil 40hp 
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Post Gas smell in engine oil 40hp
Checked my oil last night and noticed a slight gasoline smell to the engine oil (18.5 hours). Changed the engine oil before running again. Pulled the dipstick on a buddies boat and noticed the same smell. These motors only get ran for 5-7 minutes before shutting them off, short run to the blind. Could the short run and the engine never really heating up be causing the gas smell in the oil?


Fri Nov 13, 2020 8:53 pm
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Post Re: Gas smell in engine oil 40hp
As long as engine sounds and runs good this problem is usually caused by pressure buildup in the gas tank. This pressure can blleed fuel into intake while sitting. Best way to figure it out is to disconnect fuel tank when not running engine or put a fuel shutoff valve in the fuel line. See if this solves it


Mon Nov 16, 2020 10:15 am
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Post Re: Gas smell in engine oil 40hp
Thanks, it runs just fine. When I did drop the engine oil it had a grayish brown color to it.

When the boat is sitting out in the sun the tank swells up like a balloon. Is there a tank that won’t do this?


Mon Nov 16, 2020 1:21 pm
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Post Re: Gas smell in engine oil 40hp


Mon Nov 16, 2020 1:40 pm
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Post Re: Gas smell in engine oil 40hp
I’ve ran it twice since the oil change and noticed it did raise up on the dip stick just a little bit.

Also there’s a priming bulb on the fuel line. Would that have anything to do with it?


Mon Nov 16, 2020 1:45 pm
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Post Re: Gas smell in engine oil 40hp
Bulb shouldn't have anything to do with it.


Mon Nov 16, 2020 2:07 pm
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Post Re: Gas smell in engine oil 40hp
Here’s what the oil looked like, doesn’t do it justice. Not used to seeing oil look this, as I’m sure you all know it should be jet black.


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Tue Nov 17, 2020 4:48 pm
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Post Re: Gas smell in engine oil 40hp
You mentioned that you have 18.5 hours on the motor, is that the first oil change you’ve done? Did you do a break in oil change after like 8 hours or so?


Tue Nov 17, 2020 5:58 pm
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Post Re: Gas smell in engine oil 40hp
That’s the third oil change, only gets 5 or so hours of run time a year


Tue Nov 17, 2020 6:36 pm
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