Small Engines (Lawn Mowers, etc.): kubota ATS70 gas rototiller, failure point, gas tank

Question
My tiller has drained the gas tank into the crankcase and I don't understand why. The tiller was bought in 1996 and has been operated every year since. I put stabilizer in tank each fall and have never had a problem before. It was working well in October when I used it last. Yesterday when I tried to start it I found the tank empty, and the crankcase overfull.
Can you tell what has failed??

Answer
The needle and seat in the carburetor or the float itself is the failure point.  A good rebuilding of the carb is in order and should take care of the trouble.  To help prevent this in the future, install a fuel shut-off in the fuel line and be sure to shut the valve off when not in use.