joripokree,
1. The flywheel does not have a key way but just one flat edge so unless it is loose it should not cause an issue.
2. Check the ring gap and if over 10thow replace them.
3. Do not weld the blade plate unless you can balance it as it will eventually flog out the bearings (just buy a second hand blade plate).
4. Make sure that you clean the surface where the module is to get a good earth because if you haven't you will not get a good spark. Note that if the spark is a yellow colour then replace the module as it should be blue.
We have more detailed information in the parts list and manuals area of the forum.
