Spark Control Computer Spark Advance Test
- Warm engine to normal operating temperature. Disconnect carburetor switch or unground it by placing a piece of paper between curb idle adjusting screw and switch. Be sure that coolant temperature sensor is connected and working properly.
- Remove and plug vacuum hose at vacuum transducer. Connect an auxiliary vacuum supply to vacuum transducer and apply 16 in. Hg. Increase engine speed to 2000 RPM and wait 1 minute before checking specifications. Advance specifications are in addition to basic advance. See Spark Advance Test Specifications table
.Spark Advance Test Specifications
Computer Part No. Spark Advance (1) 4145907 30-38° 4145980 30-38° 4145996 30-38° 4145998 30-38° 4289034 16-24° (1) With engine speed at 2000 RPM and 16 in. Hg vacuum applied. - If computer fails to obtain settings, replace computer.