Quadrajet Problem Solving > Diagnose a Quadrajet carburetor problem

Quadrajet cold starts fine, stumbles , then clears up

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Metal Man:
I have a quadrature with a electric choke on my stock 84 Chevy truck with a 350 engine. The carb and choke has been working fine all year but now that its got a little colder it stumbles after start up. When it first did it I opened hood to see fuel coming out of fuel pump body. I replaced the fuel pump and it still stumbles but does not push fuel from pump body. I dont know if thats a separate issue but the pump is new with a regulator set at 3.5-4psi.

On a cold morning(every morning) I press the pedal down once and turn the key. The engine starts up perfectly. After about 5-10 seconds it starts to stumble and smell rich. Then after about another minute or two  it clears up and is running very smooth again. When it start to stumble I press the pedal and the stumble does not clear up but RPMs do raise. After a minute it will clear up also.

Any ideas ? I dread messing with the choke because its seems a small adjustment makes big changes.

Ethan1:

--- Quote from: Metal Man on December 10, 2014, 05:44:29 PM ---I have a quadrature with a electric choke on my stock 84 Chevy truck with a 350 engine. The carb and choke has been working fine all year but now that its got a little colder it stumbles after start up. When it first did it I opened hood to see fuel coming out of fuel pump body. I replaced the fuel pump and it still stumbles but does not push fuel from pump body. I dont know if thats a separate issue but the pump is new with a regulator set at 3.5-4psi.

On a cold morning(every morning) I press the pedal down once and turn the key. The engine starts up perfectly. After about 5-10 seconds it starts to stumble and smell rich. Then after about another minute or two  it clears up and is running very smooth again. When it start to stumble I press the pedal and the stumble does not clear up but RPMs do raise. After a minute it will clear up also.

Any ideas ? I dread messing with the choke because its seems a small adjustment makes big changes.

--- End quote ---

 Maybe junk in the needle and seat? Choke issue?

429bbf:
check if you got a crack in your hose going to the chock pull off. or if the pull off went bad. hth

Cliff Ruggles:
Sounds like a defective pull-off or leak going to it as mentioned....Cliff

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