Help with Holley Carb

[Ol'Blue]

While my Holley EFI is back at Holley Tech for troubleshooting, I though I would throw this carb I've got in the mean time.

Don't know if its been rebuilt, but it idles nice and runs good at just about every throttle position except for about 1/8 throttle as you take off. It will accelerate fine if im super light on the peddle, but give it a little more gas and it hesitate and almost quits.

Heavy throttle is fine and cruising on freeway seem to hesitate slightly. I adjusted the idle and vacuum.

Think it needs a rebuild?

 

[bronconut73]

Accelerator pump adjustment?

Just spit balling...

 

[Broncobowsher]

What happens if you try driving around with the vacuum advance unplugged from the distributor? could be a timing issue. Vacuum advance pulling too much too soon.

 

[Ol'Blue]

I adjusted the accelerator pump and it helped a lot, then change the accelerator pump cam and that helped a little.

I disconnected the vacuum advance and it seamed to make it slightly worse.

Im thinking I need a larger accelerator pump nozzle.

There is still some hesitation while at cruising speed and on freeway. May larger main jets??

So issues at heavy acceleration.

Thanks for the help guys

 

[jckkys]

What Holley are you running? The as manufactured set up is usually on the rich side. A larger accelerator nozzle will only yield a puff of black smoke. Have you checked for the presence of a check ball and weight? The accelerator pump linkage can have no slack or take up. You said adjusting it, was a big improvement. I would revisit that adjustment and see if any movement of the throttle results in a stream of fuel coming out of the nozzles.