Oh darn! Well, it was worth a shot right?!
The idle mixture screw should seriously not be forced to turn. The way I did a stuck one a long was back was to lightly tap the lower body 1/3 while apart with a small hammer to try induce a little shock to it. This was done a lot before and during a lot of oiling and rust disintegrator was sprayed on both sides of the screw. In the barrel of the effected screw is a slot of idle. Those slots were generously given ample amounts of liquid.
Remember that is a steel screw in an aluminum body so great care and patience should be used. I’ve screwed a few up on AVS & AFB carbs before. It’s easy to do, screw it up. Take your time.
Or contact Dana I think his name is, @ “Woodruff carb” to have him look at it. He does advertise here & is a FABO member before he got into this.
