My mom has a Snapper, 15hp Kohler engine. The last time she mowed the grass it ran fine. She turned it off for about an hour and it wouldn't crank again. Gas poured out of the air filter. Later, she got it running but for only a few minutes and it shut down. Could it have something to do with the carburetor?

Sounds like the needle valve is not closing and allows raw gas to pour into the cycklinder. Chances are very good that when you check the oil you'll find the crankcase is 100% full of oil/gas mix. If this is the case come back and I'll walk you through a series of steps to correct the issue.

Yes the carb is the problem, after ballengerb1 walks you through the remedy, add an in line fuel shut off valve and use it every time you turn off the engine to prevent this from reoccuring. What really happens is usually related to microscopic particules of trash/debris in your fuel.

Hello ballengerb1 and MOWERMAN2468. I came across this post and noticed it's the same thing that's happening with my Craftsman riding lawnmower (Craftsman 15.5HP OHV 42" cut hydrostatic drive riding lawn mower with a Briggs & Stratton engine (Model: 28N707 Type: 0173-01 Code: 960513ZD). As for MOWERMAN's comment, I have noticed there's dirt that got into the gas tank... which may have contributed to this happening. As for ballengerb's comment, I DID find a filled oil/gas mixture in the crankcase.

So I have a few questions:
1. ballengerb - can you please walk me through the series of steps to correct the issue? Do you have it posted somewhere else?

2. Mowerman - is there a way to clean out any particles in the system (I can take it apart and clean it out), instead of having to install an in line fuel shut off valve to use each time? I'd hate to have to do that, but if it's your recommendation, I'll see what I can do (I just don't know how to do it).

Thanks!