[cobalt327]

Originally Posted by 69chevyLWB

Cobalt327
thanks for all the help!
it has a brand new distributor in it and the engine as been running before and i didnt change anything besides the carb. pcv is plumbed all plugs checked and distributor working fine. i think that is somthing i did wrong when i rebuilt it. it idles fine sometimes then others wont idle for crap. i have never been able to give it any amount of gas when i am driving or it just falls on its face. you can revv it to the moon when its just sitting in park but with any kind of load it just nosedives.

It sounds like it's way too rich. I say that because you've never mentioned it popping through the carb. Checking the plug color for being too rich should help decide if it is or not, or have someone follow you to see if it blows black smoke from the exhaust when it's acting up- this is also an indication of too rich.

Possibilities if too rich (this isn't everything, just what I could think of in a few minutes sitting here having my first cup. Also some of these will cause a lean condition, but will cause a bog just the same):

Float level too low. Float too heavy from soaking up gas. Wrong float.

Needle and seat sticking or bad. Be sure you didn't hook the needle hook through one of the holes in the float arm- it is supposed to go on the back of the float cross piece, closest to the PP well.

Power piston stuck full rich or way too strong spring or wrong length spring for your PP.

Primary jetting way to rich- jets too big and/or rods too small. Late rods in early carb casting (rods will be too short).

APT set way too high. What did you set it at, or did you leave it alone from where it was originally?

Plugged air bleeds. Missing, plugged fuel tubes in air horn. Tubes driven in too far. Tubes that are missing altogether or that have fallen out into the fuel bowl.

Secondary air valve spring tension too loose.

Secondary pull off bad.

Secondary rods too small. (See THIS thread for more on that).

If the castings are warped, wrong gaskets, mismatched parts, etc. they can be the cause of all sorts of problems.

I already mentioned the choke being on and the ignition timing. If the timing is off or the ignition system faulty, it can run for ****, too.

[69chevyLWB]

I did forget to mention that i floored it once and it backfired once through the carb and i never floored it again incase of back things happening.
Float level is set to spec. needle and seat were vacuum checked. idles tubes are intact but holes in top are very small compared to another carb i had apart. Ignition is all up to snuff. swapped another working qjet on today so i could drive it too church and ran very well. the jets are 71 and the rods are from a remanufactured carb so i couldnt tell you what they are. has G hangar and also remaned secondary rods. air bleeds have brass restrictors driven into them. i told cliff this when i ordered parts and he said it was definetly a remanufactured carb if that means anything to you. choke pulloff works fine releases at precisely 2.3 seconds. set the air valve spring to factory spec which is 3/4 of a turn.
Also APT is set at two turns from full bottom.

[69chevyLWB]

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[V8&4spd]

Originally Posted by 69chevyLWB

I did forget to mention that i floored it once and it backfired once through the carb and i never floored it again incase of back things happening.
Float level is set to spec. needle and seat were vacuum checked. idles tubes are intact but holes in top are very small compared to another carb i had apart. Ignition is all up to snuff. swapped another working qjet on today so i could drive it too church and ran very well. the jets are 71 and the rods are from a remanufactured carb so i couldnt tell you what they are. has G hangar and also remaned secondary rods. air bleeds have brass restrictors driven into them. i told cliff this when i ordered parts and he said it was definetly a remanufactured carb if that means anything to you. choke pulloff works fine releases at precisely 2.3 seconds. set the air valve spring to factory spec which is 3/4 of a turn.
Also APT is set at two turns from full bottom.

That is the reason I have multiple Quadrajets. You get some that work just right on one engine and they don't work worth a damn on another engine.

[skyraker]

One thing that has not been spoken of here is the windup spring on the secondary throttle plates. If the windup is too weak, the car will bog on heavy acceleration. There is an allen head set screw, and the plate shaft is slotted on the end. By loosening the allen screw and turning the windup shaft the tension on the seconday plates can be changed. I always did it by feel, but I am sure that there is a better way to get it just right. Skyraker.

[69chevyLWB]

Originally Posted by skyraker

One thing that has not been spoken of here is the windup spring on the secondary throttle plates. If the windup is too weak, the car will bog on heavy acceleration. There is an allen head set screw, and the plate shaft is slotted on the end. By loosening the allen screw and turning the windup shaft the tension on the seconday plates can be changed. I always did it by feel, but I am sure that there is a better way to get it just right. Skyraker.

When i said air valve spring i am referring to the "windup" spring on the secondaries.