My friend has a bolens 1455 that ran on propane. I have no numbers on engine but can get. It's a wisconsin engine. It sat for 5 yrs he put a gas carb on it and it ran. The key switch was bad so he replaced and put new connectors on the wires. Now there is no spark except when the key goes from run to off then you get one spark. I checked out the wire and everything looks good. It has a 12 v car type coil neg side to key switch pos to solid state ign box and the box has wire that I assume go to points under flywheel. I am going to check that out and so what it is and how bad of shape it's in. Wisconsins were before my time any help would be great.
The "one spark" when key turns off is classic secondary coil winding collapse which produces voltage (and current if circuit is complete as in plug gap/ground. Seems like the points and/or transistorized switching is not working to me.