Shown left to right: screw, direction disc, knob, valve stem packing, valve stem, packing retainer(s). Not shown is the valve stem nut. Valve stems differ per model.
Threads into valve body and is secured/sealed by valve stem nut and packing.
Conical tip used to control fuel flow (e.g. clockwise it is seated against the body) and also controls the position of the fuel & air tube rod.
Made of brass, packing is graphite. Some stems and most packings still available.