Small Engines (Lawn Mowers, etc.): kohler engine, craftsman riding lawnmower, electric solenoid

Question
My Craftsman riding lawnmower has a Kohler Pro 16.5hp engine in it. My problem is it will pass all the gas out of the tank into the crank case. I am pretty sure it is from a sticking needle and seat. This carburetor has a electric solenoid on the bottom of the float bowl. I do not know what this is for.
This problem does not happen everytime. I would say about every third to forth time I cut the grass.
Any help you can provide would be greatly appreciated.

Thanks

Answer
David
The solenoid is used as a anti back fire device so when the engine is turned off the gas flow stops it going into the carburetors. To check if the solenoid is good turn the key on and yin should hear a click,you may have to get close to the solenoid as it is not very loud Do not start the engine as you wont hear no click just a lot of noise. Your carb float may be stuck or have a small of dirt in it preventing it from closing. Turn the gas off and remove the carb and clean it out with a can of carb cleaner.