ELECTRICAL TROUBLESHOOTING - continued - TM-9-2320-386-24-1-10089

TM 9-2320-386-24-1-1

0012 00

Electrical Troubleshooting (Contd)

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

3. STARTER MOTOR OPERATES, BUT ENGINE CRANKS SLOWLY

NOTE

If STE/ICE-R is available, perform NG80 Starter Circuit Tests

Test 1. Check batteries for overheating by cranking engine for 15 seconds and touching battery

terminal connections.

If battery terminal is hot, a loose or corroded connection is indicated.

a. Clean corroded connection to bright metal.

b. Tighten all loose connections at batteries, ground, and starter.

Test 2. Test specific gravity for each battery.

Perform a specific gravity test (TM 9-6140-200-14). If specific gravity of any cell is below

1.255, battery must be replaced or recharged. Add distilled water as necessary after

checking battery. Charge battery as necessary (TM 9-6140-200-14).

a. Charge all batteries not meeting requirements (TM 9-6140-200-14) and check

specific gravity again.

b. If 0.025-point variation still exists between cells within any battery, it is defective

and must be replaced (WP 0122 00).

Test 3. Test starter motor voltage.

Step 1. Set multimeter to a voltage range that will measure 24 Vdc.

Step 2. Connect multimeter positive lead to positive terminal lug of starter motor and negative

lead to terminal lug on end plate of starter motor.

Step 3. Crank engine and observe cranking voltage on multimeter. Voltage should exceed

19 Vdc. If not, charge batteries (TM 9-6140-200-14).

Test 4. Test starter motor-to-solenoid strap voltage drop.

Step 1. Set multimeter to a voltage range that will measure tenths of a volt.

Step 2. Connect multimeter negative lead to positive terminal lug of starter motor and

multimeter positive lead to starter motor solenoid ground terminal lug.

Step 3. Crank engine and observe multimeter. A voltage reading exceeding 0.2 volts indicates a

bad connection at starter motor solenoid ground terminal lug and terminal lug of

starter motor.

a. Clean and tighten connections.

b. If malfunction still exists, go to test 5.

Test 5. Test starter motor solenoid contact voltage drop.

Step 1. Set multimeter to a voltage range that will measure tenths of a volt.

Step 2. Connect multimeter between starter motor solenoid ground terminal lug 3 and lug 2 at

leads 6, 2, and 14.

Step 3. Crank engine and observe multimeter. A voltage reading exceeding 0.4 volts indicates a

defective starter motor solenoid.

a. Replace starter motor (WP 0091 00).

b. If malfunction still exists, go to test 6.