Oil dilution Yamaha bruin

Joined
Jan 16, 2021
Messages
111
Well with the snow possibly coming this weekend again I thought I would check out my snowplow machine which happens to be an 04 Yamaha bruin 350. While checking the oil i immediately noticed it smelled like gas pretty bad. The oil has a pretty strong odor of gasoline and seems to be pretty thin. If hasn’t been changed in about 3 years due to the fact it only gets used in the winter for moving snow and when it’s being used it pretty much idles the whole time very little throttle. When it’s parked it does leak gas out of the carb unless I turn the gas off and let it shut itself off. Soo I assume having a carb issue it could send fuel into the oil?? Don’t know much about then honestly, what yaall think?
 
Joined
Nov 30, 2009
Messages
1,818
Location
Warner Robins, GA
Well with the snow possibly coming this weekend again I thought I would check out my snowplow machine which happens to be an 04 Yamaha bruin 350. While checking the oil i immediately noticed it smelled like gas pretty bad. The oil has a pretty strong odor of gasoline and seems to be pretty thin. If hasn’t been changed in about 3 years due to the fact it only gets used in the winter for moving snow and when it’s being used it pretty much idles the whole time very little throttle. When it’s parked it does leak gas out of the carb unless I turn the gas off and let it shut itself off. Soo I assume having a carb issue it could send fuel into the oil?? Don’t know much about then honestly, what yaall think?

I just finished doing this on the same machine for the same issue. Either the needle is bad or the oring under the seat has failed, probably both. They will also cause it to run rich. Here's the kit you need:


Easy rebuild. Replace the plug while you're at it and replace/re-oil the air filter.

Here's a service manual like the one I bought. Grizzly 350 and Bruin are the same:

 
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