Mercury - Water Pressure Kit Gauge Installation Hardware 8M0059531. OverviewThis kit gives you the engine-side parts you need to run an analog water-pressure gauge on a Mercury 150 FourStroke. It taps into the motor's pressure port and sends a clean signal up to the gauge, so you can actually see what the cooling system is doing. Out on the water, it helps the gauge stay steady instead of bouncing or dropping out. It's a simple, practical kit made specifically for this engine.. Key Features • En