As I wrote a long time ago, the original Mosquito mangento did not work.
A couple of weeks ago I found a very scruffy looking magneto on the internet. I took a chance and bought it.
The roller / magnet is very rusty but not as worn as the one I've got. And, suprise - suprise, even if the brass parts of the startor coil are very beat up, the coil is still working. Will have to transplant the coil to the parts I've got.