Stumbled upon take off

chromebumpers

chromebumpers

solid fixture here in the forum
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On my '68 Pontiac 400 cu in automatic W/2 barrel Rodchester, it always stumbles or hesitates, sometimes feels like it will stall when applying some pedal upon pulling away from a full stop. Is this a carburetor issue?
 
without testing its difficult to diagnose for certain but it sure sounds like the carbs accelerator pump needs adjustment, or the ignition advance curve needs changes
 
I have the same issue with my tired 307 with the Rochester 2GV. I found that it improved quite a lot with the timing and idle screw adjustments suggested by Grumpy, but its still quite noticeable...

I learnt that I have to pump the bejessus out of it to get it to start when cold or after sitting for a few days (otherwise it takes a lot of cranking to get it to start..), which I'm thinking is an accelerator pump issue.... I guess that the hesitation is also caused by a tired accelerator pump.. I need to put a rebuild kit through it, but I don't want to spend $60+ on a carb that is destined for retirement...
 
I usually find when a car has been fairly well kept, running problems such as this are typically due to the carb. I just didn't think of the accelerator pump. Are the carb rebuild kits at NAPA any good? Or is a cheepo good enough for a 2V?
 
The rebuild kits are hard to find over here.... I have only seen a couple that are being sold on ebay for 2GV carbs that were on older Australian cars, but I would be taking a lucky dip if they were the right one specific for my carb....

From what I've read there's a few different types of accelerator pump plunger rubber and the quality of the rubber and its ability to stand-up to new fuel is the question... I'm not sure how to tell the difference though..
 
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