Hi TDI
I also had ignition problem with my 3W-24 .
I had good battery and good switch.
The problem was bad sensor.
TDI check the following with normal sense NO special tools.

1.After connecting the plugs with the spark plug not in the engine head switch on and off the switch of the ignition if you see spark , the unit is OK .
2.If you have coil sensor try to flip the prop few times (like when you try to start ) any spark? If yes then you are OK and maybe need little adjustment even moving the sensor back and forward to ensure spark on the right location.
3. If you have hall sensor you can do this without prop flipping.

Hope you will find my information helpfull