Mercury – Water Pressure Sensor Kit | Engine Monitoring Series | Composite & Brass Assembly | 8M0157742

Overview

When you spend a lot of time on the water, you start to notice the little things — the way your engine sounds when it’s running right, the way the hull feels when it’s trimmed just so, the sense of calm that comes when everything is working the way it should. A water pressure sensor is one of those small, behind-the-scenes parts that keeps that confidence alive. Mercury Marine part 8M0157742 gives you the reassurance that your engine’s cooling system is doing its job. Whether you’re cruising upriver, running a long stretch across the bay, or easing through a tight marina, having accurate pressure readings feels like having a steady hand on your shoulder.

Key Features

• Monitors engine water pressure for cooling system health
• Designed for 0–50 PSI applications
• Composite body with brass fittings for reliable, corrosion-resistant performance
• Engineered for accurate, real-time readings to prevent overheating
• Complete kit includes sensor and installation components

Engine & Boat Compatibility

• Fits select MerCruiser V6 and V8 MPI sterndrive and inboard engines
• Compatible with 305, 350, 377, 496, and 502 cubic-inch platforms
• Designed for Mercury two-stroke 110–200 horsepower 2.5L Jet, Pro XS, DFI, and SST outboards
• Ideal for bass boats, sport boats, cruisers, sterndrive-powered runabouts, and jet applications
• Suitable for freshwater and saltwater vessels that rely on consistent cooling performance

Performance & Practical Benefits

A water pressure sensor might seem like a simple component, but its role is anything but small. This kit keeps you connected to the engine’s cooling system in a way you can feel and trust. With accurate pressure feedback, you’ll know immediately if something changes — weeds in the intake, reduced flow, early signs of overheating — long before it becomes a breakdown.

Once installed, the difference is subtle but meaningful. Your engine feels steadier because you’re not guessing anymore. You’ll hear it in the smoother tone at high speed, and you’ll feel it when conditions shift suddenly, like when you move from deep water into a shallower stretch. The sensor provides clean, real-time data that helps you protect your engine without interrupting the ride.

The materials are built for the marine world: corrosion-resistant fittings, a sturdy composite body, and internal components that hold up to constant vibration. Installation is surprisingly straightforward. With common shop tools, most boat owners can mount the sensor cleanly and integrate it into their existing monitoring system. Once it’s in, it works quietly in the background, giving you the kind of confidence you only get when you truly know what your engine is doing.

Why Buy OEM

Engine monitoring isn’t the place to cut corners. A genuine Mercury Marine part is designed around the exact pressure ranges, electrical characteristics, and cooling system specs of the engines it protects. Aftermarket sensors may claim compatibility, but small differences in calibration or construction can mean inaccurate readings — and inaccurate readings can lead to real trouble.

Buying OEM means you’re choosing a part that fits right the first time and delivers readings you can trust. It’s long-term protection, better reliability, and fewer expensive surprises down the road. It’s the kind of advice seasoned boaters give each other at the dock: when the engine’s safety is on the line, stick with the parts Mercury designed for it.

FAQ

Q1: Which engines does the 8M0157742 Water Pressure Sensor Kit fit?

It fits select MerCruiser V6 and V8 MPI sterndrive and inboard engines, along with Mercury 110–200 horsepower two-stroke outboards.

Q2: What makes this Mercury Marine part better than aftermarket sensors?

It’s calibrated for precise readings, built with corrosion-resistant materials, and engineered specifically for Mercury cooling systems.

Q3: How do I confirm it’s the right replacement?

Check your owner’s manual or match your engine model (305, 350, 377, 496, 502 CID) or Mercury two-stroke series.

Q4: Can it be used in both saltwater and freshwater?

Yes — the corrosion-resistant design handles both environments well.

Q5: Is installation straightforward?

It is. Most boaters can install it with common tools, or it can be completed quickly by a technician.