Fortunately, the starter circuit and the main jet were fine, and I got home under my own steam.
Fuel for the pilot system comes from the float bowl and is controlled by a jet screwed into the hole in between the float bowl and the emulsion tube:
It passes into the large hole in the top of the carburetter:
And out of the round hole positioned at 9 o'clock in the square flange:
Then it passes through the gasket into the annular machined groove in the throttle body
The pilot mixture passes into the hole at 6 o'clock. From here, it goes forward to the idle screw, and passes around there into the engine when the throttle is closed; additionally, there is a hole near the butterfly which provides additional mixture from the pilot circuit as the throttle opens, to prevent a flat sport occurring before the main jet is active.
Stripping the carburetter down revealed a little gremlin in the pilot jet:
|Poor focus macro picture of a jet with extracted debris|