System Testing
- With engine at normal operating temperature, disconnect hose from distributor vacuum advance diaphragm and connect vacuum gauge to hose.
- Start engine and run at idle. If no vacuum on gauge, check hose connections between distributor and carburetor insulator block for leaks or blockage.
- When vacuum appears on gauge, attach a hand vacuum pump to vacuum advance diaphragm and draw 20 in. Hg. Ensure timing advances and vacuum remains steady. If not, replace advance diaphragm and retest.