3412, 3412C, and 3412E Generator Set Engines Caterpillar

Probable Causes

• Batteries

• Battery cables

• Starting circuit

• Starting motor solenoid

• Starting motor

• Timing pin

• Flywheel ring gear

• Transmission (if applicable)

• Engine accessories

• Hydraulic cylinder lock

• Internal engine problem

Recommended Actions

Batteries and/or Battery Cables

1. Inspect the main power switch, battery posts, and battery cables for loose connections and for corrosion. If the battery cables are corroded, remove the battery cables and clean the battery cables. Tighten any loose connections.

2. Inspect the batteries.

   1. Charge the batteries. Refer to Special Instruction, SEHS7633, "Battery Test Procedure".

   2. Load test the batteries. Refer to Special Instruction, SEHS9249, "Use of 4C-4911 Battery Load Tester for 6, 8 and 12 Volt Lead Acid Batteries".

Starting Motor Solenoid or Starting Circuit

• Test the operation of the starting motor solenoid.

• Check the wiring to the starting motor solenoid.

Starting Motor or Flywheel Ring Gear

• Test the operation of the starting motor.

• Inspect the pinion for the starting motor and the flywheel ring gear for damage.

Timing Pin

• Verify that the timing pin was not left in the flywheel housing.

Transmission (if applicable) or Engine Accessories

• Ensure free movement of the driveline.

• Remove any engine accessories that may lock up the engine and inspect any engine accessories that may lock up the engine.

The following list illustrates examples of engine accessories that may lock up the engine:

• Hydraulic pump that is driven from the rear gear group

• Air compressor

• Engine oil pump

• Other components that are driven by the engine

Hydraulic Cylinder Lock

Check for fluid in the cylinders (hydraulic cylinder lock) by removing the individual unit injectors.

Note: Drain the fuel from the cylinder head. Fuel will flow from the cylinder head into the cylinders when the unit injector is removed.

Internal Engine Problem

Disassemble the engine. Refer to the Disassembly and Assembly manual. Inspect the internal components for the following conditions:

• Seizure

• Broken components

• Bent components