Carburettor problems.

[David Stepney]

Thank you John. Yes I did. When I took the tiny brass plug out, it looked as if someone had been there before me as its 'ears' looked a bit knocked about. I didn't try to remove it, but squirted carb cleaner through it. It seems that air is drawn in through a small hole adjacent to and controlled by the mixture screw and then by a labyrinthine series of passages through that tiny jet and then into a drilling just aft of the throttle edge. The mixture screw seems to sit at the junction of two other passages: one leading from an air passage situated at about 11 o'clock to the main air intake and another leading from the idle jet.
So I'm a bit mystified as to how the idle circuit actually works.