Classic/Antique Car Repair: Tractor Generator, flow control valve, john deere 4020

Question
John Deere 4020 propane 12V tractor.  Will not start.  Replaced the starter, as the bolt inside was loose, and had to wiggle the battery connection cable to get it to start.  Tractor will crank, but will not start.  Could the generator be bad?  Before I replaced the starter, it would cause the battery cable to become very hot, and I could smell a hot electrical smell.

Answer
If the battery is charged the generator has nothing to do with the starting of the engine. If the starter is cranking the engine over then it is time to check the ignition system to be sure that you are getting spark to the spark plugs and then the fuel system. The flow of propane to the engine is controlled by an electric solenoid and a pressure regulator as well as a flow control valve the is activated by the throttle. The only time that the generator might effect starting is that if it was not working and was not recharging the battery.