Chevrolet Repair: 79 Chevrolet Scottsdale C10 350 engine,400 turbo trans, screw adjustment, vacuum advance

Question
Q.  What screw/s did you adjust?

A.   On the Rochester 4 barrel carb, my husband adjusted just the idling screw.


Q.   Have you checked to make sure the vacuum advance and centrifugal advance is working?

A.   Don't know what or where that is.  Can you give a description and how to tell if they're working?

Answer
Hey,

 Idle screw adjustment will not affect off idle operation.

 The vacuum advance and centrifugal advance are in teh distributor. There is a vacuum diaphragm and a set of weights that advance ignition timing under load and engine RPM.

Wayne