A control circuit for a lawn tractor having an engine and a power take off driven implement. The control circuit includes an inhibit circuit component for preventing operation of a power take off driven implement with the tractor in reverse. Two versions of the inhibit circuit are disclosed, one grounds an engine magneto and a second disables an electric clutch for coupling the power take off to the driven element. The circuit includes first and second override switches and an override circuit component that allows operation of a power take off driven implement while the lawn tractor is in reverse after the first and second override switches are activated in a proper order by a tractor operator.