No, I did not put new fuel in it. Can diesel go bad enough in the tank to not ignite at all while starting, particularly in a multifuel engine? The stuff that's in it doesn't smell great, but I've smelled far worse coming out of a fuel tank... a friend has a mule, and I suspect that the only way to clean that nasty fuel out of the system involves the help of a Catholic priest. Hmm, I don't remember whether he got it running again... I should ask him whether he had it exorcised.