Checking the Vacuum Advance Curve

Fig. 10 Advance Curve:

1. Turn the test bench on.
2. Turn the distributor at 500 rpm.
3. Adjust the vacuum as shown in Fig 10, and chart the degree of advance obtained.
4. If the curve graphed when tested does not correspond to the theoretical curve, adjust it using the screw accessible through the center of the advance unit, Fig 10.