I had to completely replace the loom after what I assume must have been the ignition feed to optional 110amp alternator shorted out on the engine bearer. Completely destroyed the wiring loom and could have caused a fire.
Most engine mariners fit a fuse at the starter motor to protect the ignition/engine loom but for this engine they didn’t. Well worth checking yours if you have an Isuzu fitted.
Destroyed loom
Fuse Retrofitted