Centrifugal Advance

1. Disconnect the vacuum advance hose at the distributor and plug the hose.
2. Connect an adjustable timing light.
3. Start the engine.

Timing Mark On Flywheel:

4. Check timing at idle and note result. Timing mark is located on flywheel.
5. Increase the engine speed at a steady rate. Centrifugal advance should start between:

1050 - 1300 RPM

Timing should advance steadily as engine speed increases. If not, replace distributor and retest.
6. Check advance at 2600 RPM. Reading, compared with idle speed, should be:

15° - 19° advanced

Check advance at 4500 RPM. Reading, compared with idle speed, should be:

22° - 26° advanced

If reading is incorrect, replace and retest with new distributor.
7. Turn engine off and disconnect timing light.
8. Remove distributor cap.
9. Twist the distributor rotor clockwise. The movement of the rotor must be smooth and it should spring back to its original position when released. Twist distributor rotor counter clockwise. Rotor should not move (there may be some minimal amount of free play).
If the distributor fails this test, replace and retest with new distributor.
10. Remount the distributor cap and reconnect the vacuum hose.