I still say it's a fuel issue , The dist ,coil,capacitor ,and anything else wouldn't continue to start multiple times and just run for 13-15 minutes ,It would have completely failed already .
Dirty fuel pick up in tank
Fuel line between tank and hardline under cab collapsing / cracked
Inline fuel filter
Bronze fuel filter in carb
it starts ,runs until crud in fuel line restricts flow .Won't restart ,wait an hour fuel flows back clearing line and restarts .Dies if 13-15 minutes . Why no pictures ? a good look at the condition of the rest of the engine/fuel lines and ignition could let someone give a further diagnosis .have you tried starting it once it dies using carb cleaner to see if it will fire even for a few seconds ?
