Starting Motor Circuit

In the circuit shown in CRANKING SYSTEM CIRCUIT DIAGRAM , the coil of the magnetic switch in starting motor is energized when the ignition switch is closed. The resulting movement of the plunger and pinion drive lever movement causes the pinion to engage the engine flywheel gear and the contact of the magnetic switch close, and cranking takes place.

When the engine starts, the pinion over-running clutch protects the armature from excessive speed until the switch is opened, at which time the return spring causes the pinion to disengage.