gas in oil

[gypsyman]

Last fall, my old riding lawnmower, gave up the ghost. My next door neighbor, had just bought a used, but in good shape, Saber.(John Deere wanna be) It's got a 15.5hp B&S engine. Didn't really get a chance to use it, as almost immediately, the weather went bad. Just got it out today, and started it up. Smoked really bad, and didn't seem to have enough power, stalled out right away. I had checked the oil, and it was high on the stick. So, I pulled the dip stick again, and ran some thru my fingers. It felt very thin. So, I opened the drain cock, and drained it. Sure enough, as soon as I smelled it, I could tell there was gas in the oil. Luckily, I hadn't cut any grass with it and it had only run a couple minute's.
Put fresh oil in it, and it runs just fine.
Question is, does anybody know why the gas had drained out of the tank, and into the case? Float get stuck open maybe, am I going to have to check this now, even though I plan on using it once a week. Gonna get real expensive if I have to drain out 2qts. of oil and gas everytime I want to use it. Any ideas?? gypsyman

[Curtis]

I'd say you're right about the stuck float.  It may have gotten some trash under the needle.  Wait to see if it does it again (trash may have flushed out) and then if it does you'll probably need to clean the carb real good.

Curtis

[eye shot]

My neighbor had the same problem on a brand new Simplicity rider with a B&S motor. It seems that the B&S motors have an electronic solinoid to shut the fuel off and his quit leaving fuel to run into the crankcase. I think it was supposed to keep the engine from dieseling after shut down. He replaced and not a problem since. Hope this helps.

[DDZ]

I had the same problem with my Briggs. Gas was getting into the crankcase. It ended up being the solenoid on the carburetor. 

[Rex in OTZ]

Thats why they put valves on ATV's and generators, Ive seen it happen allot with portable gas generators seen this happen on 6 diffrent gens at diirent times mostly involving bringing in cold gens(winter) in a warm shop, one Honda EU2000 had gas in oil because the gas cap vent was left in on position and it sat and filled up the crankcase in 3-4 days, also seen it happen on a snowblower, if it has a valve below the gas tank theres most likely a reason why.

assuming a carb float valve will 100% seal every time all the time is asking allot.

[JBlk]

Briggs has always had a problem with their carb float needles leaking gas.Their answer was to put a selnoid in the bottom of the carb to shut of the gas supply when the ignition switch is shut off.The quickest remendy that I have found is to get a shutoff valve that fits in the gas line.Simply turn it on when you start and off when you quit.

[gcrank1]

I like the manual shut off valve too, BUT, if you get one actually check that it doesnt leak too; mine did. At least it wont let the gas run in as quick as the malfunctioning elec. shut off, which FAILS regularly I am told at the small engine shop. I will NOT buy another one of those overpriced pieces of......(I think), Federally mandated saftey equipment.