New Carb: Engine idle races when stopped.

[gbarrett]

I had to replace my 2150 carb on the Red Wagon when I discovered it had a factory 4 barrel intake so I installed a Holly 600 with 1" spacer and now I have a problem. The idle mix seems fine, cold idle is good, warm idle is also good. When I drive to the end of the block and the truck comes to a complete stop, the idle begins to race. I called Holley and they thought I may have the vacuum advance on dizzy hooked to the wrong source so I change to the port they suggested - same problem, but I think it is a vacuum issue because I can put the truck in neutral when it races and it idles down and all is well. I have no vacuum can, and there only vacuum used on the engine is from the PCV valve, brake booster, and the distributor.

Does a vac can (or lack thereof) have anything to do with this? Modulator valve? (although it shifts fine) Does the vacuum pull on the dizzy differ from 2 barrel setup to 4? Is it possible to have too much vacuum? If so, how do I regulate it?

thanks,

Greg

[Chevelleguy]

A vacuum canister is just a storage tank.
Can't have too much and no, you can't/don't need to regulate it. The advance hook up should be the same for 2 or 4bbl. Ported (no vacuum at idle). This is going to take some hunting. Try setting the park brake while it is idling high(and block the wheels) then get under the hood and try to determine what is holding the idle up.

[Merc69]

Not to hi jack the thread but Greg that is one fine looking rig. Don't know about Naples though...worked there on a couple of assignments several years ago. Way to hot. Do know some of Collier Counties' finest though.

Again nice rig.

[Merc69]

Greg...I had something simmilar happen with the Edelbrock carb. The electric choke wire had come off and it idled very fast when not in gear. Reconnected the electric choke wire and it ran fine.