Bonjour,
Hopefully, the flywheel is not damaged, the traces that you see are the remnants of tape and its glue that I used to try to make a launcher without pulley.
Benny, one of my brothers in law lives in Birmingham, bad luck, I saw him on september i France, so you are right, it would cost me a lot to send it to you but is is VERY kind of you to have suggested it, many thanks again. And in fact, I do not reject this option, this engines worths it.