I have what I have been told a poulan 46cc engine that I want to try on an aircraft. I finally got it started and it ran strong but to restart it I had prime it with my finger over the carb to get gas in the engine. I was still trying to get the needles adjusted and I killed the engine and it back fired just before it quit. The question is ,can the magnito grow weak to where it will be hard to start but priming real wet it will start? How hot should the spark be on the spark plug? I am getting a faint spark ,but now it won't start at all now. thanks for replies

Jdfraz, I was working on my Honda conversion and before I removed the the mag and flywheel I turned the engine over and there was spark but not like the EI spark. I convert all my engines to CH electronic ignitions and the spark is very sharp. I do know you need to flip the prop pretty fast to get a mag engine to start. I think that is why the larger Zenoah's have the spring starter. Did you try a strong starter on it?

Tim

I have so called heavy starter, but have more compression than it can handle, I have been carefully using a small rope around the hub like people did on engine long ago turns it nicely. I wanted to keep it a cheap setup with regular igition but may have to go another route. I took spark plug out and turn it with starter to get the rpms up and still no bright spark.

Well... Check the gap of the coil to the flywheel and maybe the gap is too much. Don't know for sure but maybe it will help.