37-MT, 41-MT, and 42-MT Series Starting Motors Starting Motor Solenoid – Test

Note: The graphics that are illustrated in this section refer to the solenoids that are 24 VDC. Solenoids that are 12 VDC use the same procedure, but only one battery that is 12 VDC is used.

Illustration 1 g00713118

Basic solenoid circuit

A basic four terminal starting motor solenoid circuit is shown in Illustration 1. The two windings that are found in the solenoid are the hold-in winding and the pull-in winding. The windings can be checked with the following procedures.

Hold-in Winding Test

Illustration 2 g00713128

Hold-in winding test

1.Refer to Illustration 2 in order to make the connections to the solenoid. Disconnect all other leads to the solenoid.

2.Close the switch. Observe the reading on the multimeter. Use the battery load tester to adjust the battery voltage until the correct voltage is obtained. Refer to Table 2.

3.Observe the reading on the clamp-on ammeter. Refer to Table 3 for the correct amperage.
Note: A high reading indicates a shorted winding. A low reading indicates excessive resistance.

4.The hold-in winding can also be checked by measuring the resistance. Disconnect the batteries. Select the “200 Ω” range on the multimeter. Connect one of the leads of the multimeter to the “S” terminal and connect the other lead to the “G” terminal. Refer to Table 4 for the correct resistance reading.

5.Replace the solenoid if any of the above readings are incorrect.

Pull-in Winding Test

Illustration 3 g00713129

Pull-in winding test

1.Refer to Illustration 3 in order to make the connections to the solenoid. Disconnect all other leads to the solenoid.

2.Close the switch. Observe the reading on the multimeter. Use the battery load tester in order to adjust the battery voltage. Refer to Table 5 for the correct voltage.

3.Observe the reading on the clamp-on ammeter. Refer to Table 6 for the correct current value.
Note: A high reading indicates a shorted winding. A low reading indicates excessive resistance. To avoid excessive heat, do not leave the switch closed for more than 10 seconds at a time. The current will decrease as the heat increases.

4.The pull-in winding can also be checked by measuring the resistance. Disconnect the batteries. Select the “200 Ω” range on the multimeter. Connect one of the leads of the multimeter to the “S” terminal and connect the other lead to the “Mtr” terminal. Refer to Table 7 for the correct resistance reading.

5.Replace the solenoid if any of the above readings are incorrect.