Test the fuel pump. It sounds like the one-way valves on either the inlet or the output side (or both) are letting the gas drain back out of the pump-to-carb line when the truck sits idle for a while. Also, you should pull the choke knob out all the way on a cold start, forget about pumping the gas pedal, and crank the engine until it fires. Then push the choke knob in a little to keep the engine from stalling.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!