Chevy 6 Hesitation

Hi, I've got a '49 Chevy w/216, manual choke, 3 speed stick and 6 volt system. Problem is a bog or hesitation coming off idle. Also get an occasional pop back through the carb. Carb is new pro rebuild (Carter W1) and seems to react well to minor adjustments. If running above idle it accelerates smoothly(but still get some occasional minor popping back through carb). Timing is good, valves have been set, etc. Any help is appreciated.

 

Check your va***n advance.

 

accelerator pump?

 

Definitely check the vacuum advance for a leak or bad diaphram. Also check the wire that runs under the distributor plate. It might be shorting out when the plate rotates.

 

definatly look at the accelerator pump.

 

Is the heat-riser stuck in closed position? That would make it feel 'cold blooded' until the entire block/manifolds heated up. QUICK way to check that is to apply about 1/4 travel of choke and see if the accell/backfire stops.