It is a 24 volt system the engine is free runs fun the starter was rebuilt for 24volts I had it replaced when I replaced my fuel injection pump. Getting all the air out of the system destroyed the 1st starter since then I fried two starters and I noticed cables or really hot and arched to the point where they welded themselves to the battery post ,at this point only thing I can think of is replace my relay and big cable to starter everything is fine and functions as it should, oh one more thong it's always the secondary battery that receives arcing from the starter