I've got an edelbrock avs2 1906 carburetor on my 403 olds and it is idling at like 3000 rpm immediately. The fast idle screw is all the way out and not changing a thing. I can't kick it down. Choke is plugged in to a good 12v. All vacuum ports are blocked off or connected. I'm about to switch back over to a Rochester. My last step is to plug in the brake booster but I doubt it's going to make a difference.

 

It ran ok before adding the Edelbrock? I ask because I was sure that my 1406 was junk because it wouldn't idle down, then I put it on a different motor and it runs great. My intake gaskets were leaking...

 

honestly don't know only carb that's been on this thing. This is a freshly rebuilt engine only started a couple weeks ago. I'm going to pop the edelbrock off there this weekend and take a look at the carb gasket. Replace it then I may see how my quadrajet runs it. If it runs the same I know somethings up.

 

Disconnect the throttle linkage from the carb and see if it idles down. There are 2 adjustments for idle speed, 1 for the choke and 1 for curb idle. Make sure any open vacuum ports are capped.

 

Also, not a bad idea to read your vacuum w/ a vacuum gauge to obtain a baseline just so you know what you're working with.

 

What intake manifold is it ? If it is an Edelbrock spread bore manifold you might have to use the thin plate under the carb to avoid a vacuum leak.

https://www.edelbrock.com/square-bor...olds-2732.html