Have a 600 com Edelbrock 1405 carb I am having some issues with. Any time I gradually bring up the rpms and then take my foot off of the gas pedal, it stays at whatever rpm it was at before taking my foot off the gas. I can then tap the gas pedal and the motor returns to idle. It is manual choke(which I have disabled and wired the linkage to keep the butterfly open). My question is what would cause this to happen, something internal? The only other thing I can think is that my return spring(spring that pulls the throttle against the idle adjusting screw when you take your foot off the gas) is not strong enough. Any ideas?

 

incorrect alignment of throttle cable , on the pass side there is a clearance of .040 on the throttle shaft tang , my last idea would be slop in the throttle shaft . Good luck

 

Could be a weak spring or the throttle plates could be hanging on some kind of build-up on the throttlebody plate. it could also be what hotstuff said above.

 

Thanks guys, putting on a stronger idle return spring fixed it.