Sounds like a good, complete update of the fuel system. One thing to check carefully is whether the small diameter hose attached to the "PURGE" port on your charcoal can has any vacuum at curb (hot) idle. If it does, that'll explain the problem which you can remedy by installing a purge control valve (see here).
The bowl vent is supposed to have a rubber stopper that seals off the bowl vent at certain times, mine was missing. and I'm assuming I left it off when I overhauled the carb a couple years ago.
In fact I'm still trying to understand how this particular bowl vent functions, because from looking at my spare 2280, the bowl vent appears to be closed most of the time by a spring loaded arm.
This is the case with all makes and models of carb. The external bowl vent wants to be open only when the throttle is closed (curb idle), otherwise you'll get lousy gas mileage.
Carburetor operation and repair manuals and links to training movies and carb repair/modification threads are posted here for free download.
I don't think it's starving when this episode occurs
Call up www.daytonaparts.com and see if they'll sell you a "DFV" (their improved inlet needle and seat design) for your 2280. Not sure if they make one to suit.