accelerator is stuck

This is the problem everytime i start my truck it starts at 4,000 rpms and starts to go higher. when i drive my truck it increases speeds and wont stop.. i looked at the linkage nothings wrong i took the carburator off and it looks good to me anyone got any idea? maybe something in the carburator isnt right? or something was unpluged that needed to be there... this all happend after i bagged my truck.

peice of rubber holding the throttle open had it happen to m before on the way home from work i had to shift and just use clutch then turn it off at light then i got the rubber pecice out from the sela around the air cleaner and it fixed it