Weird startup when warm

When I first start my Vette, it seems the choke isn't working because there never really seems to be a high idle.

After running it for awhile, like a few mile trip to a store, then I leave it off for 10 or 20 minutes, then get back in to start it up, if I do not constantly pump the gas while turning the key, then keep giving it some juice for the first 10 seconds, it will not start or stall out.

Any ideas what is going on here?

The carb was rebuilt a couple of years ago by that carb guy in Bowling Green that spoke at C3X.  Is it time for a new carb or what?

Thanks!

Sounds like a temperature dependant vacuum leak somewhere Adam.  I've seen this happen from time to time.  When the car is cold, the parts causing the leak close up but once the engine heats up it leaks.  Could be a hose, gasket or even a valve in the carb somewhere.

It's a quadrajet.

Adam, is it hard to start like this when it is cold, or only after running for a while?
I have seen Q-pukes blow/burn out the base gaskets, and be hard to start, but that usually also makes the idle high, and very erratic. You nay have a swollen float in the carb, and a bad/worn out accelerator pump. If the float level sticks low, and the pump is worn to the point of not supplying a full shot-o-fuel, it can cause this exact problem, but it would be the same cold or hot.
Have you put any additives in the fuel while it was stored?
Not having a fast idle could simply be an adjustment to the idle screw for the choke.

I'm with Joel on this one.  If you have access to a Holley 600, you may be able to throw it on and see if there is any difference.  If there is you can make a decision to keep the Holley (I've found they are a lot easier to set up and keep in good condition) or get the Quadrapuke rebuilt professionally.  The Quads are great carbs if looked after properly and set up right.  A Holley on the other hand is so much easier to work on and set up correctly. Chips582007-05-10 15:30:45

As mentioned above, I already had it rebuilt professional two years ago.  That is why I'm thinking it is time to toss it and put something else in it's place. 

I think it has an EGR valve.  What does it look like?  What can I do to clear it out/clean it up?

Thanks!

Pass side of engine...

                                      


I've never had great luck in cleaning them, but sometimes, it does work. If it is carboned up a lot, enough to hold it open, you can open it with your fingers, while the engine is running, and possibly blow whatever is holding it open out. At the same time, you could also blow whatever is holding it open straight down into the cylinder...not really a gud thing.
It's best to remove it, and clean it with some good spray carb cleaner, while working the diaphragm up & down with your fingers....or just replace it if it is nasty. Adams' Apple2007-05-10 18:39:51

I've had this problem on my Vette (Holly), and all it usually needs is a mixture tweak, and idle adjustment.

I had a similar problem with a Ford I once owned.  Yeah I know it's a four letter word but the EGR valve played up and all I did was get rid of it and plug up the hoses and put a plate over the hole left by the valve.  I just didn't tell the inspectors that it had one originally.  Way too many hoses in a Ford so he was always confused so no problems.