old is correct on the spark. My '55 CA quit last fall and I still haven't put in the time to get it running. I had it running for a ride and was fortunate it quit at the top of the driveway. Rolled it and wouldn't fire. Lots of water in the gas as I had it outside for about a week. Now radiator off to replace hoses and should the wiring. If gas is old, I would suggest draining all and put in some fresh. I ran mine in an ice cream pail and WOW, lots of water. Break(s) in wiring could have caused your problem. Also, my experience with plugs is that you can clean them up and still they are fouled. Repeatedly cranked and pulled my late dad's Ford 600 series and was told to replace plugs even though I had cleaned them. New plugs in and it fired right up, we were amazed. I have put these in several tractors and they really work great.