Abstract: A control system for a BBC on a mower comprises a pivotal bail and a pivotal housing that is linked to the BBC. If a push member on the housing is pushed inwardly from the side of the housing before the bail is pivoted, then a pin moves to a blocking position behind the bail. Subsequent pivoting of the bail will pivot the housing to actuate the BBC. A channel in the housing frictionally grips the bail to prevent rebound of the bail when a spring force resets the housing and the bail to their initial positions after the operator releases the bail. Movement of the push member also closes an interlock switch which will kill operation of the engine if a grass discharge outlet on the mower is un-covered.