I am trying to make a 7044213 carb work on a new GMPP 390hp 350. In order to make it idle I had to turn the idle adjustment screw in a long ways. In fact when I took the carb off I noticed that the throttle plate was above the fixed idle air bypass ports (vertical rectangular ports in front of barrel).
I assume this means the idle circuit is completely inoperative but when I opened up the carb I didn't see anything obviously broken or plugged. Is there a likely cause for this?
Thanks - JB