need help with dhsa3 (picture included)

[cbrewer13]

the haynes manual describes this (thing with the fuzzy diaphragm sticking out toward the middle of the picture) as only "overchoke device". it has a small vacuum fitting on it. does anyone know what the other end of the vacuum hose hooks up to?

[mosu]

Yes, there's a small hose that connects to one of the vacuum ports sticking out from the base of the carb, beside the mixture adjustment screw. At least that's how mine was connected and it worked.

Basically the vacuum acting on the diaphragm when you give it gas with the choke engaged causes the choke flaps to open momentarily so it's not overly rich.