I'd recommend getting a new fuel tank, and as far as priming goes, turn off the truck (if it's on), move the throttle to full open, put your thumb over the exhaust stinger, and pull the pullstart a few times. If you're header tank also needs to be filled up, the fastest (but not necessarily safest) way I'd do it is to pull the pressure line that goes from the pipe to the main tank, and blow into it until fuel flows from the main tank into the header tank. Pinch the pressure line before taking another breath and/or removing it from your mouth to avoid getting exhaust gasses that are still in your fuel tank into your mouth.