4 common misconceptions about starter motors

After several attempts to turn the ignition key, if the engine turns over but doesn't start, it's often concluded that the starter motor has failed.

When attempting to start the engine, if it turns over more slowly with each try, the battery might be running down. This drained state can harm the starter motor. Prolonged cranking with low battery voltage causes high current draw, potentially leading to starter burnout. However, this is commonly misdiagnosed. Many attribute the issue to the "starter motor burning out," but the real culprits are often a weak battery, loose connections, or corrosion.

The starter motor doesn't simply burn out on its own.

Another misconception regarding starter motor failure is when the starter continues to run—or stays in mesh—while the engine is running.

Clear signs of starter motor issues include a distinct whining noise and sometimes even a burning smell. When you remove the starter motor, you might see its armature shaft and pinion turn blue from overheating. This issue is known as "over-run." It's often caused by a malfunctioning key switch or relay, leading to a continuous electric flow to the starter motor's solenoid connection—the energizing terminal.

Many incorrectly blame the starter motor, saying it "burnt out" or "runs non-stop." However, the real issue often lies in the external electrical feed to the solenoid.

Remember, the starter motor can't generate its power.

The most common misdiagnosis for this is a faulty starter motor. As a result, the starter motor is replaced without further investigation. However, replacing the starter motor can result in the same symptoms reappearing.

The root cause often involves factors like:

To correctly diagnose the root cause of the problem, check that the battery and connectors are in good condition. Examine the main cable to the starter motor and the vehicle ground connection.

If you hear a clicking or repeated clicking, it's coming from the starter motor's solenoid. This occurs due to low control circuit voltage, causing the solenoid contact to chatter from insufficient voltage.

A clicking sound from the starter motor doesn't necessarily mean that it requires an immediate replacement.

The modern starter motor is a complex and delicate component. It has a fragile outer frame and internal permanent magnets instead of wound copper coils and a heavy, thick outer frame.

There is a common misconception that if the starter motor solenoid just clicks when you attempt to start the vehicle, the starter motor is jammed. And, if you give the starter a good tap, you might free it.

This is certainly not the case. The likely reason for failure is low system voltage—a bad battery or loose connection results in high resistance in the circuit.

Always check the battery first. It's the heart of the starting and charging system.

When an installer hears the "starter motor just clicks," they might attribute the issue to the starter motor itself. In reality, the underlying cause is usually a poor battery condition. Be cautious; striking the side of the starter motor's body frame can damage its internal magnet.

In short, hitting the starter motor can make things worse.