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Old 11-26-2010, 10:57 PM
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Carburetor: Carter AFB staying open after WOT

First time post. Thanks in advance for any help. Hot rod project is a 86 El Camino with ZZ430 clone and Tremac 5 speed. Instead of using a Holly on the engine I decided to use 2 AFBs. They are Edelbrock 1404s. Everything works well except after releasing the accelerator from wide open throttle the engine almost alway will continue to run around 3500 - 4000 rpm. Throttle cable is OK. Don't appear to have any vacuum leaks. Linkage is new and is what Edelbrock markets for this setup. It finally dawned on me the maybe there was an internal carb problem so to isolate it I unhooked the linkage to the front carb. Problem continues with rear carb only in operation. Next step, hook up linkage to front carb only. Problem continues. Suggestions needed and appreciated. Thanks. Bob

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Old 11-27-2010, 08:11 AM
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carbs

are the butterfly's closing when u release them??? i'll assume u have a GOOD return spring for both carbs, not something weak that won't bring the plates to a closed position?? bill
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Old 11-27-2010, 08:16 AM
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Quote:
Originally Posted by delawarebill
are the butterfly's closing when u release them??? i'll assume u have a GOOD return spring for both carbs, not something weak that won't bring the plates to a closed position?? bill
Like Bill said...sometimes the butterfy's will be off center if messed with. Loosen the two attachment screws, close the throttle linkage, making sure they're centered and tighten. Just an idea.

Along the same line, are the throttle shafts moving side to side? Worn bushings could cause the plates to stick as well.
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Old 11-27-2010, 09:27 AM
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AFB return springs

I'm using dual springs (inside and outside) both connected to what I call "bell crank" but what is properly called I think a "primary shaft control assembly." Good ideas on checking for butterflies in contact with carb body. I'm looking at that next. Also one guy had an idea that the gaskets might be undersized and contacting the butterflies. I don't think that's a problem but I'm starting to run our of ideas. Thanks. Bob
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Old 11-27-2010, 02:47 PM
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Make sure the secondaries are closing. Could be hanging on the gasket or sticking somehow
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Old 11-27-2010, 04:10 PM
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Ditto on the gaskets, i've seen this problem before. Another simple thing is, are the carbs linkages hanging up on a vacuum hose or the air cleaner? Seen that before too.
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