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Old 07-22-2008, 12:28 PM   #7 (permalink)
88 coupe
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Quote:
Originally Posted by Oldsguy View Post
........ checking for good vacuum advanceb ........
If it's a small hesitation, it would be a good call. Lack of advance, and a vacuum leak at the same time

Quote:
Originally Posted by Oldsguy View Post
........ it is supposed to provide that first shot of advance until the centrifugal weights kick in ........
Not even close.

Vacuum, and centrifugal, advance mechanisms are totally different operations, and are not related in any way. Mechanical is tied (tightly) to engine RPM, while vacuum works primarily with the carb. When coming "off idle" there is a hesitation while the "pump shot" travels to the the combustion chamber, and one of the lesser functions of the vacuum system is to add advance, to the lean mixture, in order to smooth the transition.

Quote:
Originally Posted by Oldsguy View Post
........ the tune-up specs call for initial of 20 degrees ........
Low compression/lean mixtures need more advance.

Quote:
Originally Posted by Oldsguy View Post
........ 14 degrees of initial advance so I didn't change it ........
Try it at 20° and see if the hesitation goes away.

But don't bet on it, because I don't know as much as I think I do.

Norm
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........ You wonder why you don't get respect from the younger generation, it's cause you're a**h***s ........
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