I was wondering what that thing was. At least, I assume I was, because I already have a photo of it in my online album:
My carb is awful. It's ridiculously difficult to start the engine cold; you have to crank it for 45 seconds or more while rapidly pumping the gas pedal through its whole range, from foot off all the way to the floor. It idles way too fast, except on the rare occasion that it idles properly or stalls...and other complaints that I can't remember.
It's just old and rotted. I need to rebuild it. The last (and first) time I rebuilt a carburetor was over a decade ago in high school shop class, and I think I rebuilt a chainsaw carb and a carb from a 5hp Kawasaki. Who knows, maybe I could do the job...