Vacuum Spark Control Delay Valve

Fig 49 Vacuum Spark Control Delay Valve:

PURPOSE
The spark control delay valve, Fig. 49, provides improved driveability when the engine is cold. The valve uses a separate external thermal vacuum switch that connects ports 2 and 3 when the vacuum spark control delay valve is open. Ports 1 and 2 and 3 and 4 are connected internally.