Small Engines (Lawn Mowers, etc.): Craftsman tractor wont run-dies after starting, gas in oil

Question
I was hoping it might be the carburetor, but I think it is something more serious. Our Craftsman riding mower with Kohler OHV engine CV16S started, then died. We checked and gas is getting to the carb. We were going to see if the carburator had a stuck float or was dirty, but we noticed that there was no gas in the tank, even though we had added some the day before. We tried starting it again, and saw gas shooting out from below the valve cover, and continued after we stopped trying to start it.Also, we smell gas in the engine oil. Is this serious? BTW, if it sounds like I know what I am talking about, I don't. I only know this much because I did some searching on the web.  

Answer
It's the carburetor.  It's very common for this to happen and is caused by either a stuck float or a needle valve that's not seating.  You can try rebuilding the carb or you can just replace it.

Do not try starting the engine until this is fixed as you will quickly lose the rod if you do.  The gas will thin the oil to the point that either the rod will seize on the crankshaft or the heat generated will cause it to break.  This may ruin the engine.  Let me now if you have any questions.  Thanks, PK.