I have a 1978 GMC 3/4 ton. I am having problems with my truck flooding out while idleing.  I put this brand new carb on about a month ago. I tuned it to where it shoud be and make my truck run good, and put the Idle where I want it. But it just seems to be flooding out when I sit in traffic and then it spits and sputters when I accelerate for a few seconds then cleans its self out. Also when I go from one stop light to the next the Idle seems to change automatically. I am begining to think this new carb is junk. Anybody have any suggestions as to what else I can do or know how to fix it. Thanks

What kind of carb is it?  It sounds like your chole could be screwed up or maybe your fast idle adjustment.  

I would have to agree, it sounds like a choke or idle control problem.  I had an 82 chevy like that, it had an electric choke, and a little vacume plunger that raised the idle when the engine was cold.  both of these would either stick, or just come on, even after the engine was warmed up.  I just unhooked the choke all together, and removed the vac plunger, and never had any problems after that.  

Its a brand new Edlebrock 600 with an electric choke.  I thought I had the problem fixed, but it has started happening again. I just wish I could figure it out.  

I know this is a new carb but you might want to check the needle and seat or try cleaning the bowls out.  You might have gotten a piece of dirt in there.  I was having that problem with an older carb and the needle and seat was getting stuck.  Also after cleaning out the carb try putting a inline fuel filter in.  You can pick up cheap ones at Pep Boys that have replaceable filters.

Did you adjust the fuel mixture screws?  I had some trouble with them on my friend's Edel 600.  Do you have a manual fuel pump or an electric one?  Many electric ones produce to much volume and will push right past your seals.

If that doesn't work try to turn your idle up to about 1200 rpm's and see if it will stay constant.

Yeah I adjusted the mixture screws.  I have a manual fuel pump, so that shouldnt be my problem. I will have to try to turn my idle up. I have it set pretty low right now. It could also be cuz of the weather here too. I havent had the carb long enough to run in decent weather.  

Cold weather can affect that a lot.  You might  be right- and have better luck in warm weather.  My Holley runs way better if it is at least 40 degrees out.

if it has a mechanical secondary the linkage might need adjusting check the needles and seats maybe even rejet it with carbs it's hard to tell unless you fiddle with it.

if its flooding out then maybe you should try lowering the floats a lil bit.  

Need a vacume gage and set to highest vacume, like 17" of vacume. Also pull air bleed screws and blow them out with some contact cleaner or carb clean then reinstall. When you turn your air bleeds in all the way does your engine die. If it doesn't might be a vacume leak?? Also turn your air bleeds all the way in then back out till engine cleans up. Should be about 1 and a half turns out. What is your elevation??? this will seriously affect your tuning on factory calibration.  

higum:
<P>Did you adjust the fuel mixture screws?  I had some trouble with them on my friend's Edel 600.  Do you have a manual fuel pump or an electric one?  Many electric ones produce to much volume and will push right past your seals.</P>
<P>If that doesn't work try to turn your idle up to about 1200 rpm's and see if it will stay constant.</P>

It is not the volume but the pressure of it. You might check fuel pressure as you want about 5.5 PSI or so max.