- Low battery voltage
- Faulty wires or faulty switches
- Faulty cable or connection from battery to the starter
- Faulty starter motor solenoid
- Problem with the starting motor
- Problem with transmission or problem with driven equipment
- Internal mechanical problem
Check the battery terminals for loose connections. Also look for signs of corrosion on the terminals. Check the voltage of the battery. If the voltage during cranking is less than 12 volts for a 12 volt system or the voltage is less than 24 volts for a 24 volt system, refer to Special Instruction, SEHS7633, "Battery Test Procudure".
Faulty Wires or Faulty Switches
Turn the ignition switch to the START position. Check the voltage at the switch connection on the starting motor solenoid. If there is no voltage, or if the voltage is low at this connection and there is good voltage at the battery, check for a faulty cable or a faulty connection between the battery and the starting motor. Inspect all cables and inspect all connections. Clean connections. Tighten connections. Replace parts, as needed.
Faulty Cable or Connection From the Battery to the Starter
With the ignition switch in the START position, check the voltage at the connection of the battery cable to the starting motor. If there is no voltage, or if the voltage is low at this connection and there is good voltage at the battery, check for a faulty cable or a faulty connection between the battery and the starting motor.
Install a new solenoid.
Problem With the Starter Motor
If the solenoid works and the starting motor does not turn the crankshaft, the starting motor is faulty. Before you remove the starting motor, turn the crankshaft by hand. Ensure that a mechanical failure inside the engine, inside the transmission, or inside the power take-off is not preventing the crankshaft from turning. If the crankshaft will turn by hand, try the starting motor again. If the starting motor does not turn the crankshaft, remove the starting motor. Repair the starting motor or replace the starting motor.
Problem With the Transmission or Problem With Driven Equipment
Check the driveline for free movement. Disconnect the transmission. If the crankshaft will now turn, find the cause of the problem in the transmission and make corrections. Disconnect the PTO drives or remove the PTO drives. Again, try to turn the engine crankshaft. If the crankshaft will now turn, find the cause of the problem in the PTO and make corrections. Remove engine accessories and inspect engine accessories that may lock up the engine. The following components should be inspected:
- Air compressor
- Power steering pump
- Engine oil pump
- Hydraulic oil pump
If a problem is found with any accessory equipment, repair the accessory equipment or replace the accessory equipment.
If the crankshaft cannot be turned and the driven equipment has been disconnected, remove the fuel injector nozzles and inspect the cylinders for fluid while you turn the crankshaft. If fluid in the cylinders is not the problem, the engine must be disassembled. After the engine has been disassembled, inspect the engine for other internal problems. Possible internal problems include the following conditions:
- Bearing seizure
- Piston seizure
- Valve and piston contact