I bought the 8n from a a neighbor. He had received it from a farmer in trade for bush hog work. The farmer had converted it to 12v but the battery ran down constantly. The neighbor didnt have time to work on it so I bought it from him. I looked it over and decided to add the new gauges, exhaust, and other stuff thst came with it. While I had the hood off, I decided to rewire the entire tractor. I followed JMOR wiring diagram to the t with the exception of the diode. I put in an idiot light instead of the diode. I have the 3 wire alternator on there now. After I got it all put together, I put the hood on and cranked it up. The 8n fired right up and ran. The idiot light stayed running while the engine was running. It was my impression that it should turn off after the engine cranked. The engine ran for about 2 minutes and then I turned the key off and the tractor shut down. Few hours later I went to move the tractor out of the barn. It fired up but the starter did not disengage and made a horrible roaring noise. I turned the key off and the tractor continued to run. I jumped off and pulled the battery cable off and it finally shut the tractor down and the starter quit. Not when I try and attach the positive battery cable to the positive side of the battery I get a lot of sparks. Ive never put it on there and left it for more then a few seconds. I am afraid Id mess something up. What is happening and where do I start to look? My best description is 12v with 12v coil and electronic ignition. 3 wire alternator and everything is wired up to the best of my knowledge to JMOR DIAGRAM