Mercury - Water Pump Repair Kit 15-25HP 2-Stroke Outboards Quicksilver 85089T4. Overview. Every boater knows that when your cooling system fails, your day on the water ends fast. The Mercury 85089T4 Water Pump Repair Kit is the kind of part that keeps that from happening - quietly doing its job so your outboard can do its best. Designed for Mercury and Mariner 15-25 horsepower 2-stroke outboards, this kit restores your water pump's performance, protecting your engine from heat and the wear cause