It's intended to draw HOT air through a piece of steel tubing from a passageway near the exhaust manifold. That's needed to make an automatic choke release. It sounds like you've got some sort of Rube Goldberg manual choke conversion on an auto choke carb. That's a calibrated air leak that's built into an auto choke system.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
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