I'm having problems with my 300U coil getting so hot you can't hold your hand on it after running for about an hour. At that point the tractor runs really bad and not much power. When everything cools down it runs fine again. Its a 12 volt system with a generator and a 6 volt coil with a resistor. Been like that since the 90's with no problem. Problem started last year when I was brush hogging and I decided the coil was bad so I replaced it with a 12 volt coil that required no resistor. Same problem. I now have a NAPA 6 volt coil with a resistor again. Generator is different than last year as last fall my original one had a short and I replaced it. Seems like something is making the coil hot other than a bad coil. I have a lot play in the distributor shaft, both in and out and rotational play. I compared it to my H which has virtually no play any direction. I get how that could make it skip a little which it does sometimes but the real problem starts when the coil gets hot and it looses power. I haven't changed plugs in a long time and I have carbon core wires to the plugs which have been there a long time also. Any ideas what to be looking for?