I'm stumped! I've been messing with it for almost 3 hours now and I cant get my engine to idle at a decent RPM. It's either 500 rpm or 1200 rpm.

I have a pretty big cam, 245/252 .524/.524 112lsa so I know the vaccum signal is low at idle. This is why I have blue step up springs for the primaries. I can adjust the idle using the throtle stop screw and it goes up to what I want (750-800 rpm) and stays there. Then I give the throtle a rap and it goes back up to 1200. I adjust it down, and it drops to 500 very sharply. I think the primary system isnt closing down to let the idle system take over. How can I get it to idle decently ? Any ideas please ? Thanx in advance.

 

Are you sure your throttle cable is allowing the throttle to return all the way back? after you blip the throttle check the linkage and see if you can pull forward any. I had a simialr problem, then I bought a new double return spring and that fixed it.

 

Good call. Let me go out and check that really quick....

 

Yeah well it looks like the linkage is fine. I messed with it some more.... it still idles very low. It seems like it switches between the main metering system when the idle screw is screwed in too far and the idle circuit. If unscrew the idle screw then it stays on the idle circuit but then the throtle is not open enough for it to idle properly. Any tricks to get it to idle guys ? Thanx

 

From a friend's recommendation I drilled a small hole in each butterfly. Didnt make one bit of a difference. How big should these holes be ?!