A 1973 500C, while trying to start the machine the starter initially kicks in turns the diesel over two to three full revolutions, stops and goes about one full revolution. The positive cable becomes quite hot while something starts to buzz, like a relay or something. I have to unhook the positive cable or it seems that the starter will burn up or the cable starts smoking. The machine does run, is this because the battery isn"t strong enough to crank the machine? Thinking that maybe the starter was part of the problem I pulled it and set it up on the tracks hooked up and it engages as it should and none of the above mentioned symptoms occur. Seeking some advice and assistance Thanks