i have a holley 600cfm vac secondary carb. it runs OK when its worm but won't run for crap when its cold. when i start it up it goes to high idle at about 1500 and runs kinda OK for about 3-5 mins. then it loads up and dies if i don't rev it up. then for at least 10 mins when its off of high idle it idles real rough and slow, like 600-700 and dies after a few seconds progressively getting better as it worms up. i have a 180stat in it right now and it has to get up to 180 and stay there for about 3-5 mins before it'l run on its own without dieing. when i drive it after about 15 mins of warming up it backfires and won't hardly go it i give it much gas at all. like its running too lean.

i've tried adjusting the choke, and it dosn't do much exept make it come off high idle sooner. i've also tried adjusting the idle screws and it does nothing. what do you guys usualy set them at? i turn them in untill it runs rough then back them out about 1 turn. the vacume method dosn't realy work for me since the vacume stays about the same unless i move them a ton.

any ideas on what it could be? it's realy a pain getting it to run in the morning just so i can go 2 miles to school.

BTW:i have 65 primary jets in it right now.

Basicly there is not much wrong with it.

You have to wait till there is some heat in the manifold before the car is going to run right.

Without some heat to help the fuel vapourize the driveaility is going to be less than optimal especialy during the winter.

Part of the joys of a carbed car.

But getting the choke/fast idle set up so it works as well as it should can be a bit challenging.

Get up a little earlier in the morning so you have time to warm up the car.

Are the heat raiser passages open (intake manifold gasket) allowing exhaust heat to heat the manifold plenum?

Up here in Cold Country they adjust the gasoline formula to aid vapourization and driveability in the winter.
You may be still using "summer gas" there.

what i don't understand is why it loads up after it idles fine at high idle for the first 5 mins of running. if it would just stay running at about 1500 i'd be happy, at least i wouldn't have to sit in the car and mess with the gas for a while.

If it's "loading up" its either too rich or too lean.

too rich will carbon up the plugs. too lean will missfire
also carboning up the plugs.

When the car is cold and running at 1500-2000rpm during warm up, how far open is the choke plate?

Let me guess.... you live in a place where it's cold outside right now. Right?

If so, your problem is CARBURETOR ICING. Moisture in the air combined with the super-cooling effect of fuel being vaporized as it passes through the carb causes the water vapor in the air to condense and then freeze around the throttle plates. This slowly chokes off the airflow throuh the carb at low idle when the throttle is almost closed anyway. The ONLY thing that makes this stop is when the carb and intake manifold get warm enough to prevent this freezing from happening around the throttle plates.

Please note: this can happen at temperatures well above freezing! Even in 50* weather it can still happen if there's enough moisture in the air. The super-cooling effect of the fuel being vaporized is that powerful.

That's one reason why factory carburetor and TBI applications ALWAYS have an air cleaner assy. with a hot air hose to warm up the air entering the cab/TBI in cold weather. You may consider using a stock-type air cleaner in cold weather if this problem really annoys you.

Forgot all about carb icing.....

As Damon says, this is likely your problem.

another easy way to tell is if it's backfiring, blowing blue smoke, or blowing heavy black smoke.

i put the edelbrock back on and took out the 1" spacer. it runs a lot better cold now and dosn't hesitate at all. it idles at about 1500 for a few mins and then comes down and idles fine. i think there is something wrong with the holley, i don't think the spacer would kill the top end. it pulls a LOT harder on top now but dosn't have quite the bottom end the holley and spacer had. thx for the help though.

check your plugs if there black its rich,also the on the fuel mixture srews if you can get it running turn them all the way in,on both sides then turn them 3 full turns out make sure there both the same,also check your floats take out the big srew in the bowl with it running then there should only be gas comming out if you shake the car,one more thing check your power valve,i would put a 65 in for good vacuum,hope this helps if not email me at provgolf4u@aol.com