Years ago when I was a kid, I had a motor bike and the magnets had become demagnitized and I had no spark. I found a bare wire on the magneto coil going to ground and I disconnected it from ground and connected a 1.5 volt battery between the wire and ground. I could turn the engine over very slowly and when the points opened I got a fat spark at the spark plug. The engine ran good with the battery.
On these weedeater engines they claim to have CDI or solid state which I suppose takes the place of the points maybe. Would it be possible to connect a battery for starting purposes?