Quote:
Originally Posted by MunichTaxi
You might also confirm the vacuum advance is plumbed correctly
How does the timing advance look with a timing light?
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There are two types; vacuum and centrifical. I check the vacuum advance by using a mityvac and drawing a vacuum on the line while watching the timing mark at idle with the timing light. If the timing mark advances under vacuum and returns when the vacuum is released it is working. You'll also be able to hear the engine's speed change when it advances. It should also hold vacuum pretty well...doesn't have to be perfect but should not leak down fast or require constant pumping on the mityvac to hold it. If it leaks too fast it usually means the diaphragm has a small hole and should be replaced.
Then, with the vacuum advance disconnected I rev the engine and watch the timing mark. If it advances then the centrifical advance is working...if not then you know you have to look at it and see why it is not working. The shop manual will tell you at what engine speeds the advance should be in degrees and there is usually a curve they follow which you can use as a reference. It does not have to be perfect but should be working.