Mercury - Block Water Pressure Sensor Kit SmartCraft Data Integration Marine Electronics 8M0142696. Overview. When you spend enough days on the water, you learn to trust the quiet signals your engine gives you. A smooth idle, a steady temperature, that familiar hum when you throttle up-those little cues are what let you relax and enjoy the ride. Adding accurate water pressure data to your SmartCraft display gives you one more layer of confidence, especially when you are running hard offshore or