My back up walk behind wouldnt start. Its a old proline with a fb460. I used it two weeks ago and tried to use it today. This is how I used it all year. The gas was two weeks old also. Even though I dont think the gas was bad I drained it out and emptied the bowl. Then put gas from this week that was used in my other mowers in. I put a new plug in and had no spark with it but the old plug did spark lightly. I unplugged some of the safety wires and that didnt help. I also cleaned the air filter. A few times in a row it did try to start and when I went to take choke off died. Then I couldnt get it to repeat. So do you think this is bad gas, carb, or electrical?