Engine Compression

Prior to checking compression, be sure batteries are fully charged. During compression check, crank engine with ignition off through at least 6 compression strokes and note number of strokes required to obtain highest reading. Repeat check on each cylinder, cranking engine same number of compression strokes. DO NOT add oil to cylinder. Adding oil may cause hydrostatic lock and extensive engine damage.

1. Start and warm engine to normal operating temperature. Turn ignition off. Remove air cleaner and/or intake opening cover. Disconnect injection pump solenoid leads (fuel cutoff solenoid leads). Disconnect glow plug harness (Blue/Red stripe wire) from engine wiring harness.
2. On all models, remove all glow plugs and insert compression gauge in No. 1 cylinder glow plug hole. Crank engine and note compression reading. Repeat compression test.