Distributor Retard Control: Testing and Inspection

Fig. 21 Testing positive pressure retard system:

1. Warm up the engine fully.
2. Make sure that the idling speed and ignition timing are within specifications.
3. Disconnect the vacuum hose from the vacuum control, and plug the hose.
4. Connect the pressure tester (49 H080 740) to the vacuum control Fig. 21.

Fig. 22 Positive pressure spark retard curve:

Fig. 23 Positive pressure spark retard curve:

5. Apply compressed air gradually by turning the adjusting screw and check that the ignition timing retards Figs. 22 & 23.