Runs at FAST idle, not slow

I've been careful about setting the air/mix screw, I've tried it at 1 turn out, thru 3 turns out and no help. MAtter of fact, I can take airmix screw out and it does the same thing. I think the idle circuit is still clogged. I don't know how - I had it prof''ly rebuilt and then I rebuilt it myself. It doesn't seem to be getting enuf gas.,,,,
I replaced the Intake manifld gasket also.
Not sure what u mean by running it on propane?
I believe if I spray starter fluid in it, it would run but will try it next time