Abstract: A mechanical lock-out by which a Bendix-type starter for an internal combustion engine is rendered incapable of starting the engine if mechanism - such as the propulsion system of a power lawn mower or tractor - has been drivingly connected with the engine. The lock-out comprises a lever pivoted to the housing of the starter with a part thereof in the path of the driving pinion of the starter as it advances towards meshing engagement with the ring gear on the engine flywheel, so that the lever must be free to move with the advancing driving pinion for the starter to be operative, and a blocking member, also pivotally mounted on the housing of the starter, for movement to and from an operative position preventing such movement of the lever.