Mercury - Water Pump Repair Kit 15-25HP 2-Stroke Outboards Quicksilver 85089Q4. Overview. Every seasoned boater knows that a reliable cooling system is the difference between a smooth ride and a ruined weekend. The Mercury Quicksilver 85089Q4 Water Pump Repair Kit keeps your outboard running cool and steady, delivering the confidence that your engine is protected no matter how long the day runs. It's not the flashiest component, but it's one of the most important - quietly ensuring your engine s