Quadrajet Problem Solving > Dialing in your rebuilt Quadrajet carburetor

Just rebuilt by Cliff's, idle issue

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PaulB23:
I just received my carb back from Cliff's this week, off a 86' Monte SS (CCC system) and when first putting it on and firing it up, it idles at about 2,500 RPM.  It won't kick down and after a few adjustments, still won't get lower than 2,400-2,500 RPM.  I triple checked vacuum lines and ports, everything is as it was and should be.  I don't claim to be an expert with carbs by any means but did back out the fast idle screw under the choke all the way out without any change and also adjusted the choke coil without change.  Looking for some pointers on what could cause this to at least get the car driveable.  I'd like it to idle cold at 1,800-2,000 RPM and it should kick down fairly quickly. 

Cliff did say the carb was run on a motor, although it wasn't a CCC car apparently. 

PaulB23:
This morning I pulled the carb to inspect the gasket and for any binding issues, thinking it must be a massive vac leak.  Nothing looked out of the ordinary though, bolted it back down and it fired up and idled at 1,000 RPM or so cold.  Low but nice and smooth and the choke opened, adjusted the base idle.  Not sure what the deal was but hopefully yesterday was the end of it. 

To bump up the cold start RPM I would adjust the fast idle screw under the choke, correct?  I don't know that I really want or need it much higher but I think the stock setting is closer to 2k RPM.

429bbf:
paul wecome aboard. f.w.i.w.when its cold say around freezing when i set mine they idle about 1000.rpm as they warm up about 3 to 5 min. they run up to about 2000.and yes that is the right screw for setting the high idle adjustment.hope this helps.that also works pretty good when it gets down to 20 below.you have to give her a couple of more pumps.dean

429bbf:
couple of other tid bits i dont know where you live or how cold it gets . but my chokes are set pretty tight for cold wheather starts.so in the summer i just turn the key for a minute or so before i try to start it for the first time in the AM. that way it only takes a short while to kick off high idle.ya i could back the choke off some but why mess with some thing when you got it set to work the way you want it.dean

Cliff Ruggles:
Set the fast idle RPM's on a dead cold engine. I like them around 1200-1400rpm's.  Also fine tune the angle of the choke flap at start up if/as needed.  The choke should be fully open in apprx 3 minutes at the standard setting.  I like mine open around 2 minutes, so move the dial to the right from the base setting.  In colder weather it will stay on a bit longer......Cliff

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