I have had some weak magnets on my Jensens, none were ever completely dead.
If you can’t find anyone local to re-charge your magnet, you can send it to me and I’ll do it. I built a magnet charger a number of years ago to repair magnetos for my antique gas engines.
To remove the magnet, you’ll have to remove the entire engine base from the wood board to access the brass screws underneath holding the magnet. Keep track of the small brass blocks and any paper shims to make sure they go back together exactly as they were so the clearance between the armature and the magnet remains the same. Once the magnet is loose, just slide it sideways to clear the armature and remove it. There is no need to remove the pole pieces from the inside of the magnet.