Trying to get an early 70's 3.5 HP Sears motor running. Not getting any spark. I've mostly worked on newer marine engines and ignition systems and am unfamiliar with points / condenser ignition systems. I took the engine apart and cleaned all the connections and ignition points with sandpaper and contact cleaner and still no spark. Any ideas??? The spark plug wire goes into a round black plastic thing with metal wings around it- could that part be bad???