This type of starter motor incorporates a solenoid mounted on top of the starter motor body, which, when the ignition switch is operated, moves the starter drive pinion into engagement with the flywheel or driveplate starter ring gear through the shift lever. As the solenoid reaches the end of its stroke and the pinion is partially engaged with the flywheel ring gear, the main fixed and moving contacts close, engaging the starter motor to rotate the engine. This fractional pre-engagement of the starter drive significantly reduces the wear on the flywheel ring gear that is typically associated with inertia type starter motors.