The starter motor needs a huge current because of the amount of energy required to turn the engine over. In the interests of safety, the ignition key does not have to handle this high power, but instead actuates a current which operates the starter solenoid. A solenoid is simply
a switch which is operated by a small electrical current, but which switches a circuit capable of carrying much higher currents.
The starter motor is a powerful electric motor which drives a gear which meshes with the teeth on the flywheel, turning the flywheel and hence the crankshaft. Competent electricians can carry out repairs to the motor, although exchange reconditioned units are recommended for the rest of us not so bright sparks. If the drive pinion teeth are damaged then the unit is also best replaced (in which case, the flywheel teeth will also be damaged).
The solenoid is mounted on the starter motor. Most problems with the unit occur because it sticks (which can often be cured with a sharp tap from the handle of a screwdriver), although other faults can occur. During the course of a full restoration it would be advisable to replace the starter motor and solenoid complete with professionally reconditioned alternatives.
a switch which is operated by a small electrical current, but which switches a circuit capable of carrying much higher currents.
The starter motor is a powerful electric motor which drives a gear which meshes with the teeth on the flywheel, turning the flywheel and hence the crankshaft. Competent electricians can carry out repairs to the motor, although exchange reconditioned units are recommended for the rest of us not so bright sparks. If the drive pinion teeth are damaged then the unit is also best replaced (in which case, the flywheel teeth will also be damaged).
The solenoid is mounted on the starter motor. Most problems with the unit occur because it sticks (which can often be cured with a sharp tap from the handle of a screwdriver), although other faults can occur. During the course of a full restoration it would be advisable to replace the starter motor and solenoid complete with professionally reconditioned alternatives.
