6-2. PRINCIPLES OF OPERATION (CONT)
b. Starting Motor. The function of the starting motor is to turn the engine flywheel at a fast enough rate to
initiate engine combustion.
An electric solenoid, activated by the START switch, pulls the starting motor drive pinion into engagement
with the ring gear on the engine flywheel. At the same time, movement of the solenoid closes a set of switch
contacts which connect the starting motor armature to the battery through a set of four carbon brushes.
Current flow in the armature causes the armature to rotate. The drive pinion then rotates and turns the
engine flywheel. When the engine starts, centrifugal force resulting from increased flywheel speed, moves the
starting motor pinion out of engagement with the flywheel ring gear. Releasing the START switch causes the
solenoid to de-energize and disconnect the battery from the starting motor.