[Bus Ted Knuckle]

idle increasing when you cover the intake is indicative of a lean condition, possibly a vacuum leak. I don't think that it is your acc. pump.

check your filter(s) and post back if they are clear. The check ball being stuck is about the only way this could involve your accelerator pump.

It is possible that the carb may need to be cleaned out, being that it sat for a while. Gas turns into varnish fast these days.