Mercury Water Pressure Pick-Up Kit – 8M0059531 (150 hp Four-Stroke)

When you’re running skinny water or stretching a long run at wide-open throttle, knowing block pressure is just as important as trim angle. This factory kit threads a compact stainless-steel sensor into the cylinder head of every 150 hp EFI four-stroke (serial 1B905505 & up), feeding rock-steady data to your SmartCraft screen or analog gauge. The nickel-plated hex body shrugs off vibration and salt, while dual internal O-rings and pre-applied red sealant keep cooling water exactly where it belongs—inside the motor.

Why add it to your rig:

• Real-time 0–30 psi readings spotlight a clogged intake or tired impeller before the overheat horn wails.

• Stainless housing + epoxy-potted electronics survive 150 psi spikes and relentless pounding in chop.

• Two-pin plug snaps straight into the engine harness—no splicing or extra modules.

• Slim 1.5-inch footprint clears cowl panels and adjacent hoses for hassle-free installs.

At just 0.13 lb, the 8M0059531 kit is a small investment that pays for itself the first time sea grass or sand starts choking your pickup. Bolt it in, bleed the air, and cruise away knowing your Merc’s cooling system is talking to you in real time.