My '83 Camaro (V6, 2.8L, 2bbl Rochester Varajet II E2SE carb) was hesitating a bit. I tried a bunch of things and finally decided to rebuild the carburetor. Well, now I have real problems!
Primarily, now the car idles fine when it's cold, but as it starts to warm up, there is hesitation when I hit the gas, it will stall out unless I keep the engine revved (at about 2000 rpm), and its last breath usually ends with vapor shooting from the carb.
The rebuild included the needle seat and assembly, the pump assembly, and a new Mixture Control Solenoid, as well as gaskets. The only carb number I can find on it is 17073234, which doesn't seem to make sense, but there is no number near the accelerator pump lever, where I thought it should be.
Any ideas would be greatly appreciated!
Thanks.

 

May be a vacuum leak. Double check the vacuum connections.

 

Is the choke pulling off and opening as it should? Choke should be all the way open once the car is warm.

 

Thanks for the posts. I've checked the vacuum lines closely, and can detect nothing. But I know enough to know that's not always perfect. I hear no leaks either, but again, that's not always perfect either. It's hard to do tests with the engine quitting, but I'll look again.
The choke does indeed seem to working fine. My only concern there is that the intermediate choke rod, when cold, actually bumps up against the secondary vacuum break. That seems odd, but I don't know enough to be sure. As the car warms, it moves easily, and stops bumping.
As I think about it, the car does seem to be taking longer to get off the fast idle cam. It's been colder lately, so this might be it, but the time seems significantly longer.
Thanks!

 

When rebuilding the carb, did you carefully set the bowl float height? It sounds like a possible momentary lean or overflow stumble you're getting. Did you change the fuel filter too?

 

I did set the bowl float height carefully. It was at 11/32", I moved it to the stated 13/32" (although one book shows 1/4 inch, which I don't think is right). I did notice that the needle barely moves, whether the float is up or down. I know it doesn't need to move much to allow gas to flow, but I'd say it's maybe a millimeter or so. Does that seem normal?
Watching mist spit out the carb when it stalls out is disturbing. Can things like choke, vacuum, or float level cause that?

 

13/32"? According to the linked chart below, you're float is hanging way low. Your stumbling issue would then be due to having a dry bowl. With the top upside-down, you measured between the float and the gasket surface of the top, right?
Rochester Varajet Specs

 

Wow. Those numbers are way lower than I have in the shop manual or the info with the rebuild kit. I'll have to check that out. I can say that there is enough gas in the bowl when I take the top off to make the float float, although I don't know how fast it's emptying.
The information I have says to measure the distance between the float and the top of the bowl with just the top of the carb removed. I did this by pressing down on the needle with the float and then measuring from the high point of the float to the top of the carb. I take it you disagree?

 

No sorry, I'm thinking a different carb. Your float is set in the base, like on a Quadrajet, correct? With a straight edge across the top of the base, press down on the needle area and measure between the straight edge and the top of the float, out at the tip (highest point). It sounds like that's how you're doing it. But those measurements are way different. For your year, the .138 on that chart converts to a hair over 4/32". When you start off the line, you're giving the accelerator pump a shot, in addition to the vacuum draw calling for gas. With the lower setting you put the float at, I'm sure you're experiencing momentary fuel starvation. Look for more measurement sources if you want to set your mind at ease.

 

Thanks. My float is indeed in the base. When I pulled the old float out, it was set at about 11/32" and the carb worked although not perfectly. Once I rebuilt it, without changing the float height, bad things happened. This makes me think it's something else, but I'm no expert. I'll check a few more sources, and see if I can find a match for any of the three different numbers I have now. Complicated things, these carbs....