Overhauling a starter motor

Overhauling a starter motor

To make the engine start it must be cranked in order for air and fuel to be sucked into the cylinders and compressed. The powerful electric starter motor provides this turning force to the flywheel of the car’s engine by drawing electric current from the car’s battery.

A large switch is used to modulate the current flowing from the battery to starter motor. This switch is controlled by a solenoid.

The starter motor starts when you turn the ignition key.

If the starter motor gets weak, it will not allow the engine to crank as soon as you turn the ignition key.

The two components inside the starter that commonly fail are the solenoid (which sends electrical signals to the starter motor to activate) or the starter motor itself.

Internal components inside the starter can be replaced but most automotive manufacturers recommend that you replace the entire starter motor itself to avoid future breakdowns.

The following are the signs that your starter is getting weak:

  • Engine Wont turn over
      • The most common indicator of a starter problem is when you turn the ignition key and nothing happens. This happens usually when the starter motor or solenoid is burnt out or has an electrical issue. (This problem could also be caused due to a dead battery but if the battery is relatively new, chances are that it’s your starter motor that’s causing the problem). If this happens, contact a mechanic to inspect the starting system.
  • Starter engages but doesn’t crank the engine
      • There will also be times where you hear the starter activate but the engine will not crank. In this case it could be problems related to the gears that are connected to the flywheel.
  • Grinding noise when trying to start the engine
      • When you hear a grinding noise while trying to start the engine, it could be that the gears that connect the starter to the flywheel are worn out. Grinding could also happen inside the starter. If you notice this symptom, the best thing to do is call a trained mechanic to attend to your vehicle. Prolonging this issue could only cause serious harm to your starting system
  • Smell or see smoke when starting the engine
    • The starter is a mechanical system powered by electricity. It is possible that the the starter will overheat due to continuous power supplied to the starter or the starter motor will not shut off after the car’s engine has ignited. Because of this you might see or smell smoke coming from the engine bay. These problems could be caused due to a short circuit, blown fuse or might be due to a problem with the ignition switch.

This virtually no way to determine when the starter motor of your car could fail as there isn’t a predetermined replace interval by the automotive manufacturer.

Here are some images of a starter that has been dismantled. The motor was malfunctioning due to the armature having worn out and run its life. A new armature was placed into the existing motor and the motor is refitted to the car.

For those customers who are conscious of the price of a brand new starter motor this is a viable alternative but it will not last as long as a brand new starter motor.

Solenoid Switch 


Solenoid Switch Piston 


Starter Housing 


Motor Winding Coil 



In this particular case, the armature was replaced as it was identified as the problematic part. This part rotates between the windings thereby generating electric current.

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