well, it sounds like maybe you take the truck to a mechanic, but you might try digging out the shop manual and study the section about carburetors - you could even buy a rebuild kit and get some hands on learning experience
"When we tug a single thing in nature, we find it attached to the rest of the world" ~ John Muir "When we tug a single thing on an old truck, we find it falls off" ~ me Some TF series details & TF heater pics