Mercury - Quicksilver Engine Flushing Kit Maintenance Accessory Brass and Composite 16841Q02. Overview. Flushing your outboard after every trip is one of the simplest ways to keep it running like new. The Mercury Marine 16841Q02 Quicksilver Engine Flushing Kit makes that routine quick and easy. Designed for select Mercury and Mariner 2.5-9.9 horsepower outboards, it attaches directly to the engine's flushing port, allowing you to rinse salt, sand, or invasive material from internal cooling passa