Quadrajet Problem Solving > Dialing in your rebuilt Quadrajet carburetor

Qjet going lean at part throttle acceloration

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77cruiser:
Should be a flat tip if he did it.

mertz28:
Found the APT and opened it up 1/2 turn and now it is about dead on with good power off the line.  It still idles a little rich.  I can turn down the mixture screws about 1/2 to 3/4 turn and the engine slows and I drop about 1/2" vacuum so I left them at the highest vacuum (19").  I will hook it up to my computer and see what it does.

I tried power braking it but it just bogs down and could not get much power or rpms.

mertz28:
I did a little more tweaking and it still goes a little lean when I first get on it but................I can now for the first time power brake it and it will spin the tires.  I melted some chip seal and left a couple of nice black strips on the road.

When I first hit the gas it goes lean then I can watch it get richer and the thing loads up and starts spinning the tires.  I could probably hold it there spinning until I go through the pavement.  When I let go it launches pretty well and picks up speed in a hurry.

I need to confirm that on the opened up APT you turn the screw in to richen.  Is that correct?  That is what is happening on mine.

77cruiser:
CCW to richen raise the rods, correct. Sounds like your secondaries can use more tuning, maybe tighten the air valve spring a bit.

Cliff Ruggles:
Correct, clockwise raises the metering rods and richens part throttle A/F.

Is the 1" spacer four hole, fully open, fully divided or semi-open?  I've NEVER had any luck using spacers on dual plane intakes on small cid engines or really "mild" set-ups.  They can induce a stumble at the onset of the secondaries that is difficult to tune out....FWIW.....Cliff

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