Starter Motor: Description and Operation

The starter motor is a 12-volt unit that has the starter solenoid mounted on the drive end housing and functions as follows:
^ The motor is energized when the starter solenoid contacts are closed.
^ The starter drive engages the flywheel ring gear and starts the engine.
^ An overrunning clutch in the starter drive protects the starter motor from excessive speed when the engine starts.
^ The current flows through the solenoid energizing coil until the solenoid plunger is at the end of its travel.
^ The plunger closes a set of contacts that bypass the energizing coil, letting the holding coil keep the starter drive engaged and passing starting current to the starter motor.