Fuel Oil refers to home heating oil, which is exactly the same as off- road diesel. I've always been told that if you accidently put fuel oil in, it won't harm anything, but other than being illegal because of no road taxes, I don't think it's very good for the truck. Regular diesel is low sulfur...As for Kerosene, I don't know....Check purduefarmboy's threads...he has one on "farm diesel"