Engine Compression

Warm engine to normal operating temperature. Check compression at cranking speed with throttle wide open and all spark plugs removed. On engines with dual plug cylinders, remove exhaust side only. Ensure crankcase is at correct level and oil is correct viscosity. With compression gauge installed, use remote starter to crank engine.

Crank engine 5 revolutions (minimum) and record highest reading. Repeat procedure for all cylinders using approximately same number of revolutions. Lowest compression reading should not be less than 75 percent of highest compression reading. Cylinder compression readings should not be less than 100 psi (7 kg/cm² ).