Leaf Blowers

With a good understanding how these engine works, it is virtually impossible for it to be doing what you describe. The 2 cycle mix would need to be need to compressed to 100+ psi and a spark applied to even start the first cycle. Once running it would be constantly drawing fuel and air even at idle speed plus with the flywheel turning it would be generating the magnetic pulse to keep magneto firing once every cycle.

Once magneto kill terminal is grounded any and all stored energy would be drained from the trigger circuit in the coil. As long the kill is grounded the magneto coil should never fire on it own provided the there is no broken in the kill circuit. Even if it was open it would still require the flywheel magnets passing the coil at 300+ rpms in order generate enough voltage to trigger coil into firing the spark plug. It over 10,000-15,000 to fire a cold plug under compression with it dropping to around 8,000-9,000 volts when hot.

So basically the blower much be switch on and the starter cord pulled for it to even start. The only way I would believe what you is happening to a long term security cam recording of it doing this.

I have only seen one electric motor in my 58 yrs that would slowly stay running using self generated electricity when electric power power was removed and had a huge flywheel and run capacitors but once an load was applied it would stop.

I am going to post on a technical forum I manage and see if anyone there has ever heard of this but highly doubt it.