This was exactly the problem I had with my first experience with gas magneto generated spark engine. I thought on was on and off was off. This is how I got the kill switch backward. Fortunately I didn't cut my hand or fingers off in the process. This is so easy to do wrong.

I now think of it much like the metal tab next to the spark plug on some of the older lawn mowers. Touch the metal tab to the spark plug ( On ) closes the circuit, grounding out the spark and killing the engine. This in reality is actually off, engine is not running. Arrgh ! Man, this is so dangerous when you think about it and not surprised that more people don't get this wrong. Move the metal tab back, away from the spark plug, ( OFF ) opens the circuit, removing the grounding and allowing the engine to spark, fire and run. This in reality is on, engine is running.