After I do an engine start I do a quick engine room check. I have a set of cable cutters by the engine room door (and by each set of batteries). I IR temp gun the starter motor. If it is still running I hit the starter with a cable cutters a couple of times if that does not stop it, I cut the cable with the cable cutters. These cable cutters can also be used on a runaway voltage regulator overdriving the alternator to meltdown. In this case you do not hit the alternator with the cutters, you just cut the cable! I keep a spare a 10 feet piece of 0000 gauge cable to allow me to re-wire the starter. (While it is not enough cable to get to the main engine starting battery, it is enough to get to the wing engine starting battery. Both are 8D batteries.) I have a set of semi-truck jumper cables that are 00 gauge / 50 feet long that will work in a crunch. I have never used them on the main engine, I have used them to jump start various dinghies, including ours.