Hello folks I have a walker with 2900 hrs and it has sporatic backfiring. I'm led to believe its a valve sticking. I'm planning to replace the engine but wanted to run it by you fellas for a another opinion. Second problem is the purple wire at the key switch is getting hot when trying to start. holding the key on it cuts out cranking over for about five seconds then resumes cranking over. I am not very knowledgeable with elecrical. I replaced both relays as one seemed faulty. I would like to remedy the wiring issue before replacing the engine. If someone could give me a few pointers or areas to look or check would be greatly appreciated. I find most times its something simple that has been overlooked Thanks Rob.