I have adjusted the choke all the way in and out and the fast idle screw, and it hasnt changed a thing.
Ive heard it helps for cold starts by keeping the idle high until its warm..
Well not for me.. it does nothing.
Although when the engine starts the choke "pull out adjustment" screw gets sucked in.
Also the flap on my carb is ALWAYS wide open.
Its hooked up the swicthed 12v for sure ive tested that.
Otherwise i have a great running engine..
My stats...1990 4.2engine weber 34 card, nuttered, team rushed, no fuel pressure regulator.