Holley idle speed too hiigh

Maybe a vacuum leak? I check by using a spray bottle of water. While the car it running lightly spray around the carb and see if it stumbles....

I'll give this a shot - but if it's a carb vacuum leak, shouldn't the RPMs be too low in stead of too high?

Thanks!!

A vacuum leak will draw more air in...more air, more fire, more RPMs.

I will also take a stab at this - What about timing? Too much timing may increase idle speed too?

I don't know about this particular carb but check and see if it has a stop adjustment for the secondaries. Check the linkage for binding and also check to make sure that the B/plates aren't binding in the bores in the close position.
Good luck !

First, have you done ANYTHING to the carb recently? Maybe something you changed has disturbed the innards. Trying too hard to adjust the fuel needle can actually punch through the metal casting and cause all sorts of idle problems. Second, in some of my experiences, its often not the carb at all, but something else: a failed PCV or a cracked vacuum hose (even the big hose going to the power brakes). Resetting the timing using a slipped harmonic balencer that relocates the timing mark can inadvertently change real ignition timing. In high mileage engines, the pivot posts for the centrifugal advance weights in a distributor can stick the weights in the advance position or a spring can break, which cranks in extra ignition advance... its a long list & we really don't have enough info to guess.

This annoying problem really had me stumped for a while..that is, until this weekend.

After a few spirited runs up I-95..the high idle has gone away!

I LIKE IT WHEN STUFF FIXES ITSELF!!

Interesting...I also have a new Holley Street Avenger carb that seemed to lock in on it's high idle speed even after the engine was warmed up. I've been driving for a few weeks now and it seems to be fixing itself.

-Sean