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Old 05-23-2020, 01:46 PM
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edwardc edwardc is offline
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Quote:
Originally Posted by Captain Crunch View Post
Ed,

The idle stop screw is backed right off. The idle mixture screw seems to be set right at about 3/4 of a turn open from closed. I will try some sealant around the front of the carb, I have a 4 bolt carb. Should I have applied sealant to the carb gasket as well? Seemed risky so I didnt. I will also re tighten the carb to manifold bolts. PCV is operating correctly, I think. I can blow air through it one way.
It really sounds like a vacuum leak to me. As you know, one of the trouble spots is the front of the join seam on a 4-bolt carb. Another one is the seals around the choke & throttle shafts. An easy way to test is to shoot small amounts of starter fluid (using the little red "straw" to direct it) on each of the suspected areas while idling. A change in RPM will confirm a leak.

The PCV valve is a bit more complex than a one-way valve. In the direction that it allows flow, it should only permit flow with a small pressure differential, progressively sealing off at a higher pressure differentials. (see diagram) To test if the PCV valve is your problem, try blocking off the PCV hose by clamping it. You will have to increase the idle mixture up to about 1 1/4 - 1 1/2 turns to make up for the air that was coming thru the PCV.
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1977 Pearson P-323 "Dolce Vita"
with rebuilt Atomic-4


Last edited by edwardc; 05-23-2020 at 01:51 PM.
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