# '95 12 hp briggs gas leaking into oil while running???



## snowmanhat (Apr 10, 2010)

1995 12hp Briggs in Dynamark riding lawn mower - gas leaking into oil of motor while running. Filled up the gas tank 1/2 full and cut grass for 15 minutes - then motor shut down from empty gas tank. When I checked oil dipstick it was obvious that the gas ended up in the motor oil - about 2 inches above fill mark.
What would cause this? How can I fix it?

Thank you for your time and help.


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## glenjudy (Aug 26, 2006)

Well, the only path from the fuel tank to the engine crankcase is thru the carb.
The common cause is, for whatever reason, the float needle is not shutting off the gas flow when required.
The main reason is that the float needle is not completely seating as designed.
The carb needs a thorough cleaning, with, at least, a new needle.
Some carbs have a viton tipped needle, others have an all alloy needle with a little seat pressed into the fuel inlet passage.
HTH


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## snowmanhat (Apr 10, 2010)

Understood, I have checked the needle and seat as well as a basic visual on carb opened and I do plan on rebuilding but why does it only do it when it is running and not stored in garage for long periods of time? It runs fine while leaking if that helps.

Thanks again


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## indypower (Apr 8, 2009)

snowmanhat said:


> Understood, I have checked the needle and seat as well as a basic visual on carb opened and I do plan on rebuilding but why does it only do it when it is running and not stored in garage for long periods of time? It runs fine while leaking if that helps.
> 
> Thanks again


Vibration


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