carb stalling

[69 red fastback 20]

I have a holley 4150 600 cfm and when I give some throttle it stumbles and then it will take off. My thought is the accelerator pump, but I'm not the best on carbs, any thoughts from the people on here that are carb pros would be greatly appreciated

[Regta 10]

I think you're on the right path. first step is to see if the accelerator pump is actually working. With the engine off, and air cleaner removed, look in the top of the front barrels of the carb while with your hand moving the throttle. If the AP is working you should see a stream of gas  squirting on each side. If nothing, probably the AP diaphragm is broken inside.  The AP is located o the underside of the front bowl.

[69 red fastback 20]

Thanks for the reply, I'll check that tomorrow and see if it is shooting gas like you said, I assume if that is the problem the AP is easy to come by

[69 red fastback 20]

Well I did what Regta advised and I am getting gas when I work the throttle, so if the accelerator pump is working what else could cause the hesitation

[barnett468 418]

.

 

disconnect and plug your vacuum advance and leave it plugged until prob is solved.

 

set initial timing to 10 degrees btdc.

 

tighten distributor but make sure the bolt is not bottoming out.

 

if you have a holley or quick fuel carb, set the gas level so it is just below the inspection windows at idle . . if you have plastic windows, they must be removed to do this.

 

reset fuel mix screws.

 

take timing lite with you and check timing if it happens again.

 

[69 red fastback 20]

Thanks, I'll give it a try

[Regta 10]

Another thing is to check any vacuum plugs to see if any are cracked or broken. I had a car stumbling and found a large plug on the back of carb had cracked allowing a large vacuum leak

[69 red fastback 20]

Thanks for the response, I'm going to put on a carb spacer tomorrow night when I get home and then I'll check for vac leaks