Mercury - Quicksilver 8M0178243 Alternator Belt High-Output Charging System Rubber Composite 8M0178243. Overview. Anyone who spends real time on the water knows how quickly a great day can turn if your charging system stops doing its job. That quiet confidence you feel when you fire up the engine, check your gauges, and see everything responding just the way it should - that feeling matters. It means your gear is working, your battery is charging, and you're free to focus on the horizon instead