What Is This Part From A Carter AFB?

[cmholm]

While installing new intake manifold and carburetor gaskets on my '63 R1, I briefly turned the carb upside down. A small (1/2") white plastic barrel with a brass pin fell out. I've reviewed the Carter AFB parts in the parts and shop manuals, on-line diagrams, and watched a Carter/Edelbrock carb rebuild video, but have no clue where this bugger goes. Can anyone purchase me a clue?

On reflection, I recall hauling parts from a disassembled laptop passed my workbench on the way to the rubbish, so it's possible that this is a bit of wayward electronics. But, I thought I'd double check before I hooked the carb up.