To determine the condition of the pistons, rings, cylinder walls and valves.
JT01682 Compression Gauge Assembly
 – Run engine for 5 minutes to bring to operating temperature. Shut off engine.
 – Remove injection nozzles.
 – Install JT01682 Compression Gauge Assembly and JDG472 Adapter in injection port.
 – Disconnect fuel shutoff solenoid electrical connector on rear of governor.
Avoid Damage! DO NOT overheat starting motor during test.
Crank engine for three seconds with starting motor.
 – Record pressure reading for each cylinder. Compare readings to specifications.
Pressure listed is for 300 meters (1000 ft) above sea level. Reduce specification an additional 4% for each 300 meters (1000 ft) of altitude above this level.
– If pressure reading is below specification, squirt clean engine oil into cylinders through injector ports and repeat test.
– If pressure increases significantly, check piston, rings, and cylinder walls for wear or damage.
– If pressure does not increase significantly after retest, check for leaking valves, valve seats or cylinder head gasket.