I have been unable to chase down the source of new sooty richness on carbs 2 & 3 that popped up after a cleaning with Gumout, compressed air, and running the smallest two wires in one of those carb cleaning tools down the passage from the intake to the main jets. I confirmed good flow when I shot Gumout into the idle mixture screw hole and it shot out the pilot jet. None of my idle mixture screws have ever really done anything more than barely noticeable. Plugs were perfect before this cleaning and Carbs 1 & 4 still are. I am now thinking maybe whatever is the air intake source for the pilot circuit is plugged (or is the idle mixture hole the source so that theory is wrong?). What is the source of the air that is metered by the idle mixture screw? Does any if this sound right? Read a lot of posts but am stumped. thanks
