Been working on this new carb and for the life of me I can't get this carb to drop in idle properly.

The only way that I've gotten the idle to drop enough is to back the secondary idle screw as far off as it will go without totally disengaging the secondary. The primary idle screw is backed all the way off with a large gap, I can put pressure on the throttle to get it to drop and it will go lower but will come back up. It is also causing a problem with the transfer slot and a lean spot there during acceleration.

Also can't get the high idle to drop down to the 1500, it's staying up at 2500-3000. I've backed the high idle off as far as it will go to where it doesn't make screw isn't exposed through the plastic nut.

With the throttle not backing down I checked the throttle cable and even with it disconnected the carb still does this and the only place that I can see that could be the problem is right behind the throttle linkage real close to where the cam for the accelerator pump makes contact with the throttle linkage. I can try to take pictures but I need to find my camera's battery charger first.

 

does it have a choke?

 

Electric

 

so are there any holes in the throttle plates? if not there must be a vacuum leak somewhere.

 

No vacuum leaks, I've double and triple checked for that. Plugged all ports with no improvements, double checked all gaskets and there are no high uncompressed areas.

 

then there must be something binding in the linkage maybe a bent throttle shaft.

 

This thing is brand new, never been used before. I'm sure that it has to be a problem with a screw that I haven't adjusted yet. Maybe even a cam that I might need to change.

 

there is only the primary and secondary idle adjustment. if something else is wrong i would send the carb back. have you called holley?

 

What about your timing, do the installation instructions say anything about adjusting the timing?

 

is this a new/fresh motor? or one that was running fine before the new carb?

holley spends enough money in thier R&D that just bolting it on right outta the box should yeild better results then it sounds like your getting

see if some one will lend you a carb that you know works fine... after bolting it on and everything seems to be ok (minus minor adjustments) take that junk and return it for another one... if there is still an issue, well, my friend, find that vac. leak.

 

Timing is set at 14* base.

The motor was running at idle better than this when I had the Edelbrock on it.

Haven't called Holley yet, this here was my final resort before calling them.

 

Check the secondary throttle adjustment, that would cause it.

 

I already have it backed off as far as it will go and if I turn the screw to open the sec's then it just makes the idle even higher.