idle mixture screws don't make carb respond on 7027231 carb

[cadillacproject]

I have a 7027231 carb on a 67 Cadillac Eldorado with a 429 stock engine.  Adjusting the idle mixture screws all the way in or out have little effect on the idle speed.   I rebuilt the carb with cliffs parts but I did not remove the idle tubes just cleaned all passages very carefully several times and dipped the carb etc.   Car run fine on the road but idle is a little rougher than I like.   Idle is solid however but screwing the idle mixture screws only has a minor impact even if all the way in or almost all the way out.  Vacuum is strong and steady (18 inches at 650 rpm) once the car is nice and warmed up.   

[Cliff Ruggles]

If you aren't getting any nozzle drip, and see a speed change turning them in, it's fine....Cliff

[cadillacproject]

Ill check on the nozzel drip.   Thank you.   Turning them in does not seem to make what I would think was a significant change.   On the passenger side I get some change but on driver's none at all whether in or out.

[Cliff Ruggles]

Most likely one or both of the idle tubes are plugged up some.  Common problem with q-jet rebuilds, and why you don't have any control with the mixture screw(s)......Cliff