Hey all,

I have a 72 small block 350, It has a Carter AFB Competition Carb. Just wondering if any of you know off hand what the proper idle speed is. I have set it by primarily by ear and feel. It seems to idle a little rough so before I start farting around with the needles I want to make sure the idle is correct.

Can you accurately set the idle speed using the Built in Tach? Or do I need some kind of diagnostic tool to help?

Thanks!

I would first check for any vacuum leaks around the carb and on the manifold. Can be done with a vacuum guage or misting starting fluid (ether) around the bottom of the carb...be careful doing it....if the engine revs up higher then you've got a carb to manifold leak (gasket).
If everything is good...look at the timing. Not sure where it should be, all depends on your cam and compression. I've got a 350 CI with a mild street cam and 10.5 compression and I run mine about 2-3 degrees advanced.
If that's all good..then look at the air fuel mixture...may not be getting enough air.I just replaced my q-jet with a Holley 650 Avenger and Edelbrock intake and had similar idle issues. On my Holley, I turned the mixture screws all the way in and then backed them out 1 and 1/2 turns and she purrs like a kitten. Not sure on the AFB but my q-jet mixture screws were out 4 full turns.
Your car should idle at around 900-950 in park and 600-650 in drive. I used the cars stock tach to set mine and it worked just fine.
Hope that helps.

Thanks for the response, I will try some of that and let you know. This site is the best!!

Just wanted to add that my 1980 idled horribly when I first bought it. When I took off the carb and intake I saw that the intake gasket had turned into some kind of burned potatoe chip, and crubled just about as easily. After adding a new one, and a edelbrock carb and intake. It idles very smooth. Just a thought.

Hey,

I examined everything in there and it all runs fine once the idle speed was correctly set. The problem actually seems to be that my choke is not functioning. I got in there and cleaned it and loosened it up so it moves freely but still when the engine is cold the butterfly is sitting wide open.

I have a Carter AFB competition carb does anyone have any idea where I should start.

Thanks!

Hey, there, Jer. This one came up last weekend. Look up the post "cold starting". We've had a lot of fun with it.

Maybe something there will be of some help.

John

I have a manual choke on mine and I love it, it adds to the whole classic feel, and non car guys have never seen them before. You get to be an expert at using it after a while.