Quadrajet Problem Solving > Dialing in your rebuilt Quadrajet carburetor

7044211- Lean Idle?

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tmny277:
Hi all, I just discovered this forum though I've been using Cliff's book for a few years.
I have a 7044211 installed on a 74 L82 Vette.  The motor is nearly stock except for Dart Iron Eagle heads.

The motor has a slightly rough idle and intermittent surge under light throttle (about 2000 rpm).
It pulls 15" of vacuum at about 900 RPM, which is the stock idle.  The idle is not steady though, it floats about 20 rpm up or down but can spike up to 50.  When I screw the mixture screws in the idle will get really rough and nearly kill the engine.  When I adjust out I get to about 4.5 turns before they stop responding.  When I partially block the air horn I can get up to 16" of vacuum before killing the engine.
I'm thinking that it might need more fuel at idle, possibly due to free-er flowing heads??
What do you guys think?

Caveats-  The carb had an incorrect air horn when I bought it so I got a replacement from another 74 model year carb (7044213 I think). This new  air horn is slightly warped. The gasket takes up the warpage easily though as far as I can tell.

Thanks!

tmny277:
More Info- The carb was set up un-modified with stock jets and rods, 75 jets and 43 rods.  And rebuilt using Cliff's book as a reference.

Thanks again!

429bbf:
i would take a very good look at the electrical system on this to start with before i would blame the carb. do you still have points? even if its converted id look at it . electrical problem give a lot of carbs a bad rap.i worked with a guy once that changed 3 carbs before he realized it had a stuck set of timing advance weights.fwiw

tmny277:
Thanks 429,  The ignition was the first thing I checked.  It is also completely new, Distributor checked, new points, condenser, rotor, cap, coil, wires, plugs.   Dwell and timing checked and re-checked.

Do you think my supposition about needing more fuel is incorrect?  I'm looking for any feedback in this area.
According the Cliff's book my cam is somewhere around his second idle example with 222/222/114 specs.  So, I'm thinking it needs more fuel at idle....

429bbf:
what size are your are your idle tubes, dcr, and idle air bleeds now . that would give a guy a good idea of what your dealing with . did you totally strip the carb and measure everything and put shaft bushing in . a small vacumn leak through the throttle shaft will cause the symtoms you have .fwiw

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