[HopSing]

I have just inherited my late father's 1981 37 ft Newell Coach. The old thing is in pretty rough shape cosmetically, but seems mechanically sound. It had been sitting on my dad's lot for the last 6 years only being cranked up intermittently, but had not been started in the last 2 years. I got it running and have driven it. I would only get up to about 10mph. I've determined that the fuel filters were stopped up and will be replacing them today. I've checked for water in the fuel/ water separators and they checked out free of water. I also opened the main tank sump drain, and no water there. It has about a little less than half a tank of diesel in the main and about a half tank in the aux. tank. The fuel is about the color of tea and probably 6 or 7 years old. Since i found no water, I'm thinking I can just add some good anti-gelling fuel treatment/cleaner and after changing the filters, use this fuel. Does anyone have any experience with using old fuel like this. Also, it has a 4 cylinder generator motor. Does anyone know what kind of engine this is? The main engine is a Detroit 6V92? or something like that. Any help or guidance here is much appreciated.