Carb hangs on rpm

[Sirsmiley9]

Holley carb doesn’t return to idle when taking my foot off the gas sometimes. When I take my food off the gas the rpms don’t drop instead I have to lift up on the gas. Moving the accelerator cable return springs doesn’t stop it from hanging, and I’m not sure what other part of the carb would fix it.

 

[Joey4speed]

If you disconnect the acceleration cable, will it still hang up if you work the throttle at the carb? If it's better it was the cable.
If it still hangs up it's the carb itself.
I have a similar issue but I know it's the cheap aftermarket acceleration cable that's the culprit.
It's binding internally and usually hangs up about an extra 300 to 500rpm.
I tried beefing up the return spring but just made it harder to push the pedal and still hung up on de-acceleration.
I have a good mopar cable that I'm sure will be smooth, just haven't found the time to install.
You can see the difference, the aftermarket is much thinner, almost like a bicycle brake cable.

 

[DrCharles]

It is also possible if you're using a 4-hole gasket for the butterflies to hang up on the gasket... as Joey points out, first disconnect the cable and see if the carb itself is sticking.

 

[Oldmanmopar]

Always tighten the carb with it in wide open position.

 

[Tooljunkie]

Always tighten the carb with it in wide open position.

Never ever crossed my mind, makes sense though.

 

[Tooljunkie]

Holley carb doesn’t return to idle when taking my foot off the gas sometimes. When I take my food off the gas the rpms don’t drop instead I have to lift up on the gas. Moving the accelerator cable return springs doesn’t stop it from hanging, and I’m not sure what other part of the carb would fix it.

We can all assume its a 4bbl, but a holley 2bbl does this too.

 

[AJ/FormS]

It is also possible that your carb is fat and you have an intake vacuum leak. In this case the carb is not hanging open at all, but the engine is instead just burning the fuel it sucked out of the intake that was just hanging out. The extra air could even be coming from the PCV or a leaky brake booster. Extra fuel could be coming from the choke, the accelerator pump system, or just a high fuel level.