Vacuum Retard
- With distributor in test stand, check retard at vacuum settings shown in specifications. See appropriate DISTRIBUTOR ADVANCE SPECIFICATIONS table in this section. Replace vacuum unit if tests indicate vacuum diaphragm unit is inoperative, out of calibration, or leaking.
- Most types of vacuum diaphragm units are factory pre-set and cannot be adjusted. However, on some dual diaphragm units, maximum vacuum retard setting may be raised or lowered by turning an eccentric, located at side of vacuum unit.