Cliff's Quadrajet Parts and Rebuild Kits

Quadrajet Problem Solving => Diagnose a Quadrajet carburetor problem => Topic started by: dblhh on November 18, 2008, 09:11:33 AM

Title: Rough idle after choke opens
Post by: dblhh on November 18, 2008, 09:11:33 AM
My 1977 TA has a Pontiac 400 with the Quadrajet carburetor. After it has been parked for awhile, you can start it up and it runs just fine with a smooth idle. After about a minute -- it seems about the time the choke opens up -- it begins idling really rough and will barely keep running. While the engine is warm, it continues to have a rough idle everytime it is started. Is this likely a problem with the carburetor or something else?
Title: Re: Rough idle after choke opens
Post by: Cliff Ruggles on November 19, 2008, 06:28:12 AM
Have you tried adjusting the idle mixture screws after the engine is fully warmed up?  The symptoms indicate a lean condition at idle......Cliff
Title: Re: Rough idle after choke opens
Post by: dblhh on November 19, 2008, 12:44:16 PM
Have you tried adjusting the idle mixture screws after the engine is fully warmed up?  The symptoms indicate a lean condition at idle......Cliff

Cliff,
Thanks for the reply.
No, I haven't tried adjusting anything on the carburetor yet until I had an idea I was looking in the right area for the problem. I'll give it a try.
Thanks again,
Herrel
Title: Re: Rough idle after choke opens
Post by: Cliff Ruggles on November 30, 2008, 06:56:28 AM
"but when kicked down off of high idle. the engine wants to slowly die."

This often indicates the timing is falling off and may be combined with a lean carburetor condition, choke pull-off opening the flap a bit too far, etc......Cliff