Generally you can keep an engine running by spraying starting fluid into the carb. I've done this to disprove or prove fuel system problems. The six volt starter should spin the engine well with 12V.
What sputters? Starter making noise? Backfire? Afterfire? Is it firing and kicking back? Have you ever seen the truck run? If not, how long has it been since it ran?

 

Just a SWAG, have you checked the exhaust system for mouse nests or other vermin? About the only way to ascertain you have no exhaust blockage is to loosen the pipe somewhere around a manifold. I've seen nests block an exhaust completely. Also seen air cleaners blocked.

 

Ah, south FL is a good clue. Have you done a compression check? I'd bet on some stuck valves, as well as the mouse and insect nests Ray pointed out. One member pulled a dead mouse out of the oil pan down there. For that matter, did you pull the pan and clean out the sludge?