# Honda GX31 Fuel getting into crankcase oil



## gfmiller (Mar 17, 2014)

I'm trying to fix a Honda GX31 off a brushcutter, for a friend. I was told that when the engine is running it loses power. I've cleaned the carbi and checked that the needle is seating (using vacuum pump). I noticed that the crankcase oil had been overfilled (so I thought) so I reduced that to the correct level and tested the machine. It ran OK, however after rechecking the level of the crankcase oil I found that the quantity had substantially increased, again. Has anyone had the same trouble or know what the likely cause would be ?
Thank You
Graeme


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## 30yearTech (Sep 14, 2006)

A leaking diaphragm on the fuel pump can cause gas to enter the crankcase on certain types of fuel pumps.


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## gfmiller (Mar 17, 2014)

Thanks 30yeartech I will have another look.


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## paulr44 (Oct 14, 2008)

I will add to 30yr. as it's the same church, different pew - these small honda engines often get overfilled with oil and if overfilled can foam, preventing the fuel pump in the carb. from working correctly. We've even seen this on 25HP Subaru engines with a separate fuel pump but still CC acuated. I don't have it in my head, but I think those engines only hold like 6 oz. of oil - the OWNER'S manual will tell you.


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