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Discussion Starter #1
68 Chevy panel wagon with 78 Firebird 305, 2brl rochester. Just had carb rebuilt. Idles great. Runs smooth and steady, plenty of get up and go once your rolling. Only thing is if you step on it much, it stumbles and/or dies. Starts right back up, no dieseling when you kill it. If you ease into it from a start it goes fine. if your rolling slow and goose it, dies immediately. 65 is top speed (powerglide and low gears) and it is extremely smooth and responsive at that speed. Any ideas?
Thanks,
trapperjack
 

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accelerator pump is not working. when the blades open up, you go lean, so lean that there is not enough fuel to fire with the extra oxygen. if it has a manual choke, close the choke a bit, it should not do what your experiencing, but will run rich.
 

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Discussion Starter #4
It did this "stumble" before I had the carb rebuilt. It's been suggested by a friend that the vacuum advance diaphragm might be bad and causing this. The reason I had the carb rebuilt was I thought the stumble was the accelerator pump wasn't working right. Got complete kit and new float. It runs MUCH better now, smooth idle, and once you get past that dead spot it roars like it should.
What do ya'll think about the vac. advance? How can I check the accelerator pump?
Thanks for the replies,
trapperjack
 

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I tend to go along with the vacumn advance being bad......a new one does not cost very much. Also I have seen the mechanical advance get rusty etc. and stick and hang up so check that also.
 
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