How to Bench Test a Lawn Mower Starter

If you are having trouble starting the mower, the electric system could be one of the possible problems. If you press the start button and the mower fails to start, the cause could be a faulty starter motor. Other possible causes could be corroded or loose wires. After checking the different causes and you fail to notice the issue, bench testing the starter is the next step.

In the detailed guide below, we will assist you to bench-test your mowing machine’s starter.

Before bench testing a lawn mower starter, assemble the following tools:

  • A jumper cable
  • A cleaning brush
  • Battery

With the tools ready, you need to test and check the connections and other parts before bench testing the starter. Below are some of the parts that require checking.


Test the Battery

The lawn mower battery requires checking before looking for any issue with your motor, as it supplies electrical current to the starting motor to start the machine. If you have failed to charge the battery correctly charged, the supplied current won’t be sufficient to turn the motor.

Keep in mind that most lawn mowers use 12-volt batteries, and therefore a multimeter can help inspect the battery. The machine battery is in a pristine state if it reads 12 volts on the multimeter. However, if the battery reading is lower than 12V, it means that its condition is deteriorating slowly, and you will soon need to recharge the battery or replace it.

Inspect the Wiring

A mowing machine can’t start if its wiring is faulty. Typically, it cannot manage to supply the electric current to the motor if connections are loose or broken.

Check the Starter Solenoid

The lawn mower’s solenoid is a critical player in the working of the starter motor. When you rotate the lawn mower key, the battery electricity is transferred to the motor solenoid. Then it connects the motor current directly from the battery, making the motor start turning.

The mowing machine cannot start if this connecting solenoid is defective. In most cases, a defective solenoid causes a click when you try to turn the mower on, but the lawn mower won’t turn. Once you confirm all these parts are in a good state, it’s time to do a starter bench test. The below guide outlines how to carry out starter motor bench testing.

Park the Machine and Switch it Off

Before removing the key, park the mower on a level surface.

Remove the Plug

To ensure that the lawn mower does not accidentally start, disconnect the spark plug cable.

Uninstall the Starting Motor

Find the starter and battery in the lawn mower. It is simple to find the battery under the mower seat or hood. However, finding the starting motor sometimes is difficult, and following the wire that connects the solenoid to the battery going to the starter is the best way. 

The starter should be below the mower engine cover. Take out the mower’s starter and use a wire brush to brush off the dirt in the wiring system and connection points. Make sure you remove dirt and dust in the motor to allow connections.

With Jumper Cords, Connect the 12V Battery to the Starter Motor

To test the motor’s starter, use a 12V battery and jumper wires. The red wire is negative, and the black one is positive. The jumper wire has a couple of ends. Connect the battery with one of its ends to the  (-ve) post, and then attach a red wire and black to the (+ve)  post. To avoid sparks and short circuits, ensure you connect properly.

Confirm the Starter Motor is Working

You should attach the red wire end to the starter frame and the black cable to the starter terminal. In case the motor head starts to spin, the machine’s motor is in a good state. Usually, the starter head rises to allow smooth flywheel engagement. In case of  a faulty motor, it produces a click sound, and rotation stops. In this case, you will need to replace the starter.


Bench testing the mowing machine’s starting motor is simple, and it’s possible to do it at home without challenges. Before removing and testing the starter, you may need to first inspect the mower’s other electrical components. In case of a defective motor, you will need to replace it. When you follow the guide above, you should be able to figure out the issue, solve it and get the machine’s starting motor back to life.