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Won't idle when cold

asappin

Full Member
Joined
Oct 14, 2014
Messages
210
Just replaced my auto lite carb with a Holley 2 barrel 350 CFM carb. When I try to crank it without pressing in the pedal first it won't fire. If I press the accelerator pedal then try it fires right up but then dies. It has the manual choke and it seems to not be working or maybe I just don't have the carb set correctly. I haven't done any adjustments to the air fuel mixture. Once the engine is warm it will idle fine. I also hear a light popping noise out of the exhaust from time to time while idling.

I tried to do a search but couldn't find any results like mine.

Thanks
 

oleguy74

Contributor
Bronco Guru
Joined
Mar 26, 2008
Messages
2,034
Loc.
calif city ca
idle mix a little lean.adj idle mix screws.also there is a fast idle adj on the choke.adjust that also.there should be instructions with carb.if not get a holly book.
 

B RON CO

Contributor
Bronco Guru
Joined
Jun 29, 2016
Messages
2,484
Loc.
Statesville, NC
Hi, check the choke cable. Pull it out closed (right?). Pump the gas, start(right). Drive out and push choke in (right)? Is this how it's going?¡
 
OP
OP
asappin

asappin

Full Member
Joined
Oct 14, 2014
Messages
210
If I pull the choke out till its almost completely closed it will stay running but once I push it in it stalls and tries to die and idles really low. I believe I have a vacuum leak around the spacer. I spray carb cleaner around the base and the idle changes. Would this cause it not to idle?
 

oleguy74

Contributor
Bronco Guru
Joined
Mar 26, 2008
Messages
2,034
Loc.
calif city ca
vacume leaks usually get high idle.still need to fix those.like I said,you need to adjust carb.when you pull choke out,there is a high idle cam thet steps up the idle.your curb idle needs set also.see post two.
 

dave67fd

Bronco Guru
Joined
Sep 24, 2010
Messages
2,864
Although most Holleys work fairly well right out of the box, taking the time to read through and performing this procedure should get you running great. You will have to take care of the vacuum leak first. If it's your base gasket you either tightened it too much, too loose or unevenly. If you think you tightened too much, get another gasket.

Tunning is actually quite easy.. Pick yourself up a vacuum gauge and a short piece of vacuum hose.
There's also several youtube videos on it as well. Bsic tunning is the same for the 2 and 4 barrel just double the adjustments with the 4.

http://www.junkyardgenius.com/holley/tune01.html
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
51,613
And make sure your ignition system is putting out a good spark too. A weak ignition can make things act funny and seem like carb issues as well.
AS the others have said, fix the vacuum leaks first. You can't tune anything out until you do, or you'll just be re-doing all your tuning once you do finally fix it/them.

Play around with your ignition timing too. Add some advance to see if that helps.
After fixing the vacuum leaks too of course.

Paul
 

Broncobowsher

Total hack
Joined
Jun 4, 2002
Messages
37,063
It's been awhile since I have had to deal with a holley choke. But I know they have a fast idle cam on them. It is to add a little throttle when the choke is active. I'm pretty sure that you have to tickle the throttle to let that wedge slip in and give you the cold idle speed.

Occasional pop out the exhaust is probably ignition. Too much initial advance, weak plug wire(s), condenser getting weak. Hard to guess which part in the system it could be.
 
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