Lawn tractor woes

We have a Cub Cadet, relatively new as has only done 20 hours. Recently had a problem where the petrol drained through the carburettor and filled up the sump rendering petrol and oil useless, and creating a cloud of white smoke so dense that you could have hidden in it. (probably would have suffocated too but that's beside the point)
Anyway, what is the likely cause? OH suspected needle valve in carburettor stuck open with a bit of muck, but, after taking that off and carefully checking, it was found to be in excellent order and was clean and free of any pollutants. Float working as it should and no explanation to be found as to cause. Anyone had this problem with a lawn tractor, Cub Cadet especially and is it a known fault?

Check the fuel shutoff solenoid, do a quick google on it for walk through vids. Good luck.

did you check that the float in the carby is actually floating and not punctured in any way? Is it still under warranty? 20 hours is not long even if it has gone past its warranty, I would take it back to dealer.

Float fine, no chance of taking it back to dealer. Solenoid is a possibility.

very strange indeed. I would think that the shut off solenoid is placed before the carby and is there as a safety feature and not to maintain the fuel level in the bowl?? Try this page for clues...