Small Engines (Lawn Mowers, etc.): Fuel in Crankcase, shutoff valve, riding mower

Question
I have an older riding mower with a B/S 12 hp I/C engine.  Today it started to slow down and die every time I made a turn.  If I stopped for a few seconds it would run like normal again.  After a few minutes it completely died and would not re-start.  When I went to check the oil level, all I could see was fuel.  I completely drained the crankcase and got mostly fuel.  Is there anything I can check or do I need to take it to a small engine repair shop?

Answer
You need to clean the carb, tank and lines.
Your carb acts just like the toilet in your house. It has a float that pushes up a needle to shut off the fuel flow when the carb is full. When your toilet float sticks you here it running and you jiggle the handle. Unfortunately you can't hear your carb leaking and it doesn't have a handle to jiggle.
Clean the carb, only you know if you can handle this job or if you need to take it to a dealer. You noticed I didn't tell you to take it to a small engine repair shop. I said take it to a DEALER. The main reason techs work at small engine shops is because they can't hack it at a dealer. It's almost May so don't be surprised if there is a 3 week wait.
Another option is to buy an inline fuel shutoff valve. Use it every time you park the tractor. This will probably get you by until June when the wait times will be shorter.