Quadrajet Problem Solving > Diagnose a Quadrajet carburetor problem

Choke pull off

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tayto:
just curious what model regulator you are running?

dlphil10:
Im running a Holley 12-803 regulator.

dlphil10:
Found my old 2 barrel carb and checked its choke pull off. It starts to release at 5inHg, but was super quick. I used a piece of plastic to make a restrictor like you have suggested Cliff. I got it to 1.25seconds. I know thats pretty quick, but it's just about right with 1 turn on the secondary air valve spring.

Since the pull off releases at 5inHg now instead of 1inHg, secondaires are actually useful under heavy loads like pulling hills. Is there a vacuum value that you look for the pull off to start releasing?

Cliff Ruggles:
Not really.  I look at the release time using a mighty vac pump.  It needs to be pretty quick for best full throttle performance, but not instant.  A good starting point is about 1.5 to 2 seconds to fully release........Cliff

dlphil10:
I ordered another pull off and got it to 2.25 seconds. This combined with 3/4 turn on the air valve spring provides the best results.

I have 2 targets now. A very slight off idle stumble that I've helped by using stiffer power piston springs. I'm trying to locate a stiffer spring that starts to lift at 12inHg, or maybe 13inHg. I figured that would imitate the APT system with later model carbs.

The second is my main concern. It's a few faint pulses in the exhaust at 1800rpm after going WOT from a stop. It happens a little while after going WOT, but then it clears right up at 2000rpm and is smooth until 5200rpm. Could I need larger jets (currently using 72s)?

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