Truck won't fire.

Does it have spark? Pull the coil wire and hold it 1/2 in. from a metal part of the engine then have someone crank the engine while you watch for spark. If it has HEI pull a plug wire and insert a screwdriver into the boot and then hold the metal part of the screwdriver 1/2 in. from a metal part of the engine block then have someone crank the engine while you check for spark. It sounds as if the carburetor has a problem with the choke and the accelerator pump so it's due for rebuilding. You should also check the timing in case the timing chain jumped. I hope this helps. Take care.