So i just installed a refurbished 600 Holley that i orderd from Summit to put on my 302 and it all looks and hooked up fine but when i go to set the idle speed i cant get the rpms to go below 1000. Itll slow to then but wont go any lower, the screw will still turn out but doesnt do anything, and id like to be able to run around 850 at idle. would it have anything to do with the air/fuel mixture? any help would be greatly appreciated as i cant wait it back on the streets.
What vacuum is your engine pulling? your power value might be too big? Have you checked the float level?
Yep, either a vacuum leak or the secondary idle stop needs adjusted, is letting in too much air in the rear barrels.
Make sure the rear throttle blades are closed. You are supposed to set them to where they just cover part of the opening in the bore but I can never get one to run smooth like that. I always adjust the rears to the pint they are closed. The adjustment screw is beside the hook up for the secondary diaphram and you either have to use a small 90 screw driver or pull the carb and turn it over to get to it. If it is too far open the car will idle on the secondaries and the primaries will have no affect on the idle. That or a vacuum leak like said or too high of initial timing could also cause it. My bet is on the secondaries though clint
To make the secondaries easier to adjust while the carb is on the car I put a set screw in from the top. To adjust, with the engine off, hold open the secondaries and stick an Allen wrench in the top and turn about 1/8 turn at a time from fully closed and then try it. When the primaries no longer control the idle speed, back off the secondaries a little. Mine are pretty much the same way as Clint's, almost closed.
Vacuum leak...Or as stated:secondaries cracked open...Also: Warped throttle base assembly.(not uncommon with holleys)will cause a vacuum leak. If you use a thick gasket and crank the nuts down on the carb base...You will warp it.Use the thin paper base gasket and just "snug" the carb nuts down.Spray some water at the base of the carb and see if the idle changes.It may be your problem.Re-built holleys done by someone other than persons in the know or holley tend to be problematic.Good luck!!!
If your car is equipped with a curb idle solenoid it may have to be adjusted to allow the throttle to be set to idle.
What did you set the timing at ? That should be done first before doing anything with the carb. You could have a vacuum leak, if it sounds like it's running rough.
Warped carb base is a good suggestion also. I bought 3 new Street Avengers one after the other and all 3 were warped to some extent. I went back to a rebuilt 1850 I had after that mess. clint
