I believe you found my video on how to tell when the timer is working. Here is a link to how you get the flywheel off. https://youtu.be/RWgE9XiIBnk?si=0DPHxi1leXgM0vw4 I suspect the flywheel has been on and off many times without a torque spec. If you feel you need one search for at bolt torque chart. It will have a speck for that size thread. Whenever you have had the flywheel off , after you have run it, you should check the nut to see that it’s still tight. If your flywheel has holes the size of nickels, you need to be careful you don’t over tighten the nut as you can crack the flywheel. Away from home and don’t have my picture files to show you what to look for. It you have the large holes it’s not a problem. Ware from use may be the cause of your timer hitting the rivet. You may need to make a shim to put under the timer.
A "Boathouse Repair" is one thats done without having tools or the skills to do it properly.
