Mercury - Flushing Kit Cooling System Maintenance Tool Rubber, Stainless & Plastic 44357T2. Overview. Keeping your cooling system clean is one of the easiest ways to extend your engine's life. The Mercury Marine 44357T2 Flushing Kit lets you do just that - quickly and easily. Designed for Mercury and Mariner outboards (20HP and up) and most MerCruiser sterndrives, this simple kit connects to a standard garden hose so you can flush away salt, silt, and plant debris after every run. Built from dur