Tillotson carb question

[TMarsh]

Have Tillotson x carb on my 30 coupe. Everything seems normal. When I tried to adjust the idle down a little bit, I noticed the idle screw was not hitting the idle stop. I was curious if the butterfly could be installed wrong so as not to allow the butterfly to not completely close therefore not allowing the idle screw to touch the stop. With the linkage disconnected it still did not hit the idle stop.
Any ideas?