Hello... This is a common problem with the 35amp stator systems. I have never gotten a good answer why it happens . Remove the flywheel and check and see if others are cracked. Below is a repair kit and OMC part #'s for repair kits that is avalible so you wont have to find a new flywheel. Inspect stator real good, any damage to exposed wiring or coils, replace it. Inspect the timer base for gashes. I would replace the rectifier as it may start to leak. The OMC recommended flywheel epoxy adhesive for bonding a magnet to the flywheel is OMC #431929. The OMC magnet replacement kit (magnet & epoxy) is OMC #584304, the posting below is from Promarine.