# Gas in crankcase



## WildcatKY (Sep 28, 2012)

I have a B&S 13hp I/C engine Model 28M707, Type 0112-01, Code 9311114E that gas is getting into the crankcase only while it is running. This happened last fall and I thought it was carb related, so I took it off and cleaned it thoroughly and replace the float needle valve. Changed the oil and it started up first try, no smoking or loss of power while cutting, ran like new. I only used it twice before storing it for winter. Got it out this spring, started first time. I also installed a fuel shut-off valve in the gas line. Now I am again getting gas in the crankcase. Appears to be happening while running. What could be causing this to happen? Head gasket, rings ?? As I stated, it does not burn any oil, it doesn't smoke, and has great power while cutting. Any help appreciated.


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## Don L (Jul 14, 2012)

If your engine has a fuel pump it could be the problem.


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## paulr44 (Oct 14, 2008)

Don L said:


> If your engine has a fuel pump it could be the problem.


Yup. Only 2 ways for it to get into the CC. Through the carb., which really can't happen when it's running else it'd be running so rich it'd stall, or the impulse operated fuel pump as Don L indicates. The fuel pumps are about or less than $30 and your local dealer probably has more than one on the shelf waiting for you. Brand doesn't matter, Kawasaki, B&S, Kohler, all pretty much use the same exact pump just in a different wrapper.


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## WildcatKY (Sep 28, 2012)

Thanks DonL & Paul. It does not have a fuel pump, gravity feed gas tank directly to carb. Any other ideas? Thanks.


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## 30yearTech (Sep 14, 2006)

If it's a gravity feed setup, then the carburetor has to be flooding for fuel to make it into the crankcase, there is no other avenue besides the fuel pump that would allow entry into the crankcase. If it's happening while running then it would have to be running rich as Paul suggested, and it would not be running good.

If you have the Walbro carburetor, just replacing the float needle may not be enough, as the brass seat is usually the actual problem, I always replace them both, when I run across this issue. If you have the Nikki carburetor, then the o-ring that seals the metering body to the carburetor at the fuel inlet may be leaking. 

In either case, if you turn off the fuel supply, then it should not allow fuel to make it into the crankcase. If the carburetor is flooding while the engine is not running, the engine will usually be hard to start or crank over.


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## WildcatKY (Sep 28, 2012)

Thanks 30yr, It has a Walbro carb LMT 18, and when I had the carb apart I took it out for a good cleaning and upon visual inspection it looked okay. Never gave it a thought that it could be bad. I will replace it and see what happens. Thanks for the heads-up. Learned something new today.


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## WildcatKY (Sep 28, 2012)

Thanks 30yr: Replaced inlet seat and it is not leaking now. Runs fine. Thank you for the info.


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## Gerome (Sep 25, 2011)

30yearTech said:


> If you have the Nikki carburetor, then the o-ring that seals the metering body to the carburetor at the fuel inlet may be leaking.


Could you be more specific regarding which o-ring you are referring to?


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## 30yearTech (Sep 14, 2006)

Gerome said:


> Could you be more specific regarding which o-ring you are referring to?


See post #6 in your thread. There is only one o ring in the picture, not the rubber valve body gasket. It goes directly around the fuel inlet on the valve body.

http://www.hobbytalk.com/bbs1/showthread.php?t=400956


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