Ignition Timing: Adjustments

Vacuum Advance Hose:

1. Warm up the engine to normal operating temperature.
2. Turn all electrical loads off.
3. Disconnect the vacuum hoses from the vacuum control unit and plug the hose.

Test Connector:

4. Connect a tachometer to the engine and connect a jumper wire between the test connector and ground. Check the idle speed. The idle speed should be 850±50 rpm.
5. If the idle speed is not to specifications, proceed as follows:
a. Remove the blind cap from the air adjusting screw and adjust it.
b. After adjusting the idle speed, install the blind cap and disconnect the jumper wire from the test connector.
6. If not already done, remove the wire from the test connector.

Timing Marks:

7. Connect a timing light to the engine and check the ignition timing. The initial timing should be 12±1° BTDC.

Adjusting Ignition Timing:

8. If the ignition timing is not within specifications, loosen the distributor body installation bolt and adjust the ignition timing by turning the distributor.
9. Connect the vacuum hose to the vacuum control unit.
10. Connect a jumper wire between the test connector (Green 1-pin) and ground.
11. Ensure that the transmission is in neutral, then check the idle speed. The idle speed should be 850±50 rpm.

Adjusting Idle Screw:

12. If the idle speed is not within specification, remove the blind cap from the air adjusting screw and adjust it.
13. After adjusting the idle speed, install the blind cap and disconnect the jumper wire from the test connector.