I am looking at truck to buy, a 92 F-350 custom IDI. The only issue with it is is that it has be roll started. Once running it stays running, and once it's been running if you start it again fairly soon after shutting it down it will start again. The owners have checked the batteries, and done starter, solenoid, and glow plug relay. What does this sound like? I was thinking fuel pump, filter, or fuel line, but don't have a lot of experience. Also, out of curiosity, could I add a turbo to this motor or would that be a bad idea?