Quadrajet Problem Solving > Diagnose a Quadrajet carburetor problem

Throttle plates closed, but still nozzle drip

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Marx3:
I just put together a 17081282 for a completely stock 170 hp 350 in a '79 Caprice.
Car had been sitting for 10 years when I bought it. I drove it home and it was running allright.
Since I am milling the heads a little and putting in a 214/224@.50 cam, I made a few changes.

Bypass .080
Tubes .036
Dcr .047
Upper iab .075
Lower iab .075

Mab's resized to .070
72 jets and 44 rods

Installed new throttle bushings.

I can't get the idle down below ~800 and this is with the idle stop backed all the way out: throttle blades are closed.
I am getting a steady stream of nozzle drip this way. Pulling a vacum hose does nothing to idle rpm, opening up the throttle a little will increase idle speed, but does not change the steam of drip.
Timing is around 15 initial and is getting ported vacum. Applying manifold vacum will increase the idle.
I have checked and adjusted all four throttle plates to ensure minimum to no light can be seen around them.
All hoses are checked and/or replaced and all but the necesary vacum ports are capped off.
I have even been spraying carb cleaner pretty meticulously everywhere to look for leaks.

What am I missing?

77cruiser:
Float level?

Marx3:
Thought so too. Checkes it, found it to be at the usual 1/4"
Lowered it a bit, just to rule it out.

I just don't get how the nozzles can flow fuel in idle, when the throttle is actually closed.
I have the rear of the car on jack stands, because I have been doing brake work, so the car is not level. Could this cause the drip?

von:
Check your choke fast idle adjustment to be sure it's not holding the primaries open a little even when the choke blade is fully open. If that's not it, there's probably a vacuum leak somewhere.

Marx3:
Already checked :-) This is far from my first Qjet, that's why I'm puzzled.
I am 100% positive the plates are completely closed.
I agree, the engine is getting air from somewhere, I just can't figure out how. And HOW is it sucking fuel from the nozzles with the plates closed...
Typical nozzle drip occurs when the plates have to be opened too far, to make the engine idle...

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