Cub Cadet will not start. What does the oil sentry do?

It will crank, there is gas getting to the carb, and there appears to be fire on the plugs Something seems to be keeping gas from the cylinders. I have checked fuel solenoid. What does the oil sentry do. If that fails, does it cut off power,gas,or etc. The only response I get from CUB CADET is 'Go to Authorized Cub Cadet Service Center for istance'