I think your choke idea was right on. I checked and found the rubber cover where the cable enters
the carb was busted (worn out with age). Pulling and pushing a bit on the cable had the engine doing
some weird things. I'll take the cable out and see if I can't come up with some new rubber covers.
Give me something to work on today.

Gotta love Geeses (if they're made in Mandello)!