Vacuum Retard
- With distributor in test stand, check retard at vacuum settings shown in specifications. If tests indicate vacuum diaphragm unit is inoperative, out of calibration, or leaking, replace vacuum unit.
- Most types of vacuum diaphragm units are factory pre-set and cannot be adjusted. However, on some dual diaphragm units, the maximum vacuum retard setting may be raised or lowered if necessary by turning an eccentric, located at side of vacuum unit. See Fig 1.