Cliff's Quadrajet Parts and Rebuild Kits

Quadrajet Problem Solving => Dialing in your rebuilt Quadrajet carburetor => Topic started by: dougs69 on March 30, 2013, 08:56:10 AM

Title: Tuning the idle circuit
Post by: dougs69 on March 30, 2013, 08:56:10 AM

So far I'm thrilled with the results from all the things I have done. Its nearly perfect.

  Stock 1972 pontiac 350
Carb 17058201
Main jets = 76
Rods= .044
idle tubes= .036
Down channel restriction= .052
upper idle air bleed=.070
lower idle air bleed=.077
idle bypass air=.071
main air bleeds =.120
holes under mixture screws=.081
 
All parts bought from Cliff,   

problem is a rough idle.  mixture screws out 5 turns.    apt up 5 turns.
The car performs well, no complaints
Im thinking it needs a bit more fuel at idle.    should I shrink lower idle air bleed to .070, or open up dcr to .055, or do something with the holes under mixture screws? or a combination?  I dont want to make the wrong move, its so close!
you have all been such a huge help for me, i want to wait for your advise and expert opinions. Thanks Doug

Title: Re: Tuning the idle circuit
Post by: Cliff Ruggles on March 31, 2013, 03:22:52 AM

Smaller lower idle airbleed will help.  Take it down to .070", and then open up the down channel restrictions if needed....Cliff

Title: Re: Tuning the idle circuit
Post by: dougs69 on April 21, 2013, 08:03:24 AM

That did the trick! shrunk lower idle air bleed to .070 and opened up dcr to .055. 
The car idles well, mixture screws out 3 turns, apt up 5 turns and running better than it has in 26 years. Thank you all so much for your help.

Title: Re: Tuning the idle circuit
Post by: Cliff Ruggles on April 28, 2013, 04:45:42 AM

Good news!  The idle airbleeds, as you found out, have a major impact on fuel delivery to the engine with any given settings.....Cliff