That Carter has a diaphragm accelerator pump. They deteriorate and leak or get stiff and don't pump gas when you goose the throttle. A clear sign that the diaphragm has a hole in it is a rich condition especially at idle. Heavy soot on the plugs will be very apparent.
I'd buy a kit from CarbKing Jon and clean and rebuild it. Have him include the red accelerator pump diaphragm. They are supposed to hold up better to ethanol.
