Quadrajet Problem Solving > Diagnose a Quadrajet carburetor problem

off idle stumble

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clumsum:
Hi, I'm new to this forum but have heard Cliff is the man when it comes to rochesters. I have a stock '70 pontiac firebird that I recently got a rochester 7040573 for and it has a dead spot when I crack the throttle open under load. I really have to give it gas and ease the clutch out slowly to keep it from dying. I also feel this dead spot in every gear as I first apply throttle. Once past that dead spot it goes like a raped ape. I checked the accelerator pump by looking down the throat of the carb with the engine off and seeing gas squirting when I worked the throttle and I tried moving the rod to the pump to give it a bigger shot but it didn't help. The guy I got the carb from had it on a gto and said it ran fine for him and that he had it rebuilt a few years ago. Anyway I am not really familiar rochesters so I hope someone on here will be able to point me in the right direction as to what to try to fix this. I guess I'll go out and try to find Cliff's book at the book store first. Thanks

Frank400:
Was that car running before you put that carb on ?  If so, was it running good and what carb was on it ?  Your timing curve may have something to do with that as well.  What is the motor in that car ?  Is it stock or modified ?  More details will help.  Frank.

clumsum:
It was running good before I swapped the rochester that was on it for this one. I only wanted to put this one on because it's the right number carb for my engine. It's an unmodified ram air III 400 engine.

Cliff Ruggles:
I would install one of our SR kits, and primary jets and metering rods while it's apart.  The 7040573 is the California emissions version, and pretty lean on the primary side.  It will respond well to giving it a tad more fuel, we can supply the correct items with the rebuild kit.....Cliff

clumsum:
Cliff, I'm in the middle of reading your book right now and so far it is very helpful in understanding how these work. I'll take your advise and get your kit and the new rods and jets. Can I buy them on line or do I have to call?

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