When the ignition switch is moved to the start position, battery voltage is sent to the starter solenoid contacts. This will energize the solenoid windings and cause movement of the solenoid plunger and shift lever which causes the drive pinion to engage the engine flywheel ring gear and the solenoid switch contacts to close. When the solenoid switch contacts close, the starter motor is energized and cranking takes place. As the engine starts, the pinion overrun clutch protects the motor armature from excessive speed until the ignition switch is opened. Once the solenoid windings are de-energized, the return spring causes the pinion to disengage. In order to prevent excessive overrun, the ignition switch should be opened immediately when the engine starts.