I bought a 345 that ran when I bought it . Had carb leak so I had a kit put in it and fired right up went 200 ft and quit. Wouldn't start back up. Pulled a plug wire to check spark . Spun it over and it started. Cut it off and put wire back on it won't start. Pulled wire, it started. As soon as I start to put wire on it cuts off. What could it be?