The pilot circuit is metered by the pilot jet and the air screw (which gets its air from the outer hole on the back of the carb) however.... the slide is not completely closed when the throttle is shut, there’s a small gap underneath. You’ve probably got around 3/32 of open gap from the slide cutaway when the chose is down it closes this off.... the purpose doing so causes more vacuum to be drawn through the welsh plug and from the pilot circuit.

If your chokes aren’t touching the bottom of the bore then there’s a cabling issue.


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