I was in the same situation. Fortunately the batteries were charged and it started right up. The diesel was a bit funky as well as the tank being dirty. I had repaired the tank when I bought it, welding rust holes and then sealing it with a polyurethane product. This made flashlight inspection (once strainer is pulled) easy. Well, after 18 months, the fuel had turned murky. So I drained it (went into step son's M1009), then swabbed the gunk out of the tank.
Now with fresh diesel, it runs great. Remember, most retail diesel contains biodiesel which has a much higher affinity for water. It only takes a few parts per million of water to murk diesel. This makes bacteria grow which causes corrosion.
I have not changed the oil in over 3 years. It still looks like new, despite 15+ hours of use.