Vacuum Spark Delay Valve: Testing and Inspection

Fig. 64 Vacuum Delay Valve:

To test the operation of the vacuum delay valve, Fig. 64, connect a tach and a timing light to the vehicle. Run the engine at idle, observing the ignition timing. Have an assistant open the throttle to 3,000 RPM and start a stop watch at the same time. Note the amount of time it takes to achieve vacuum advance. Replace the vacuum delay valve if it does not open within the following time frames: Brown 1-3 seconds; White 4-8 seconds; Green 16-24 seconds.
NOTE: when replacing the vacuum delay valve make sure that the colored end of the valve is pointed toward the vacuum source.