Carb wont idle

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Nov 21, 2016 | 07:55 PM

Harley Hill

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Carb wont idle

So I have a 302 that I just put an air gap manifold and an edelbrock 1405 carburetor that I updated with an electric choke and throttle bracket. When I start my truck it starts right up, has a high idle then instantly drops idle speed and dies, even sometimes spitting through the carb. If I keep it running by giving it about half throttle it stays running and doesnt surge or anything but the second I bring the idle down just a little it will surge then die. Ive checked everywhere that I could have a vacuum leak and everything is plugged what could be the problem?

Nov 21, 2016 | 09:49 PM

RileyCarroll

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Quote:

Originally Posted by Harley Hill

is your choke operating correctly? Have you tried using a vacuum gauge to tune the carburetor, if so, what did it say? Have you checked the timing and firing order after you swapped intakes

Nov 21, 2016 | 10:23 PM

Harley Hill

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Im not sure on the choke, I dont have a vacuum guage, but the timing and firing order are perfect.

Nov 22, 2016 | 05:32 AM

Dave145

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From: Burlington, WI

Carryover from your last thread, but what is the timing set to?

Is the carb new or used/rebuilt?

Spray brake clean around the carb an intake. If rpms go up or it stumbles, there's a vacuum leak.

Carbs need to be adjusted with a vacuum gauge. They're dirt cheap and invaluable. What is your idle speed set to?

Nov 22, 2016 | 11:04 AM

hurst1979olds

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A good base setting on the carburetor idle mixture screws is 2 1/2 turns from seated. Then adjust for max vacuum. But that initial adjustment will be enough where the engine will run and idle.