Mercury – Water Pump Assembly | MerCruiser Cooling System | Marine Aluminum Housing | 8M0113736

Overview

When you’ve spent enough time on the water, you learn to trust the parts that keep your engine cool and calm, even when the day heats up. A dependable water pump becomes one of those unsung heroes — working quietly beneath the deck so you can enjoy the ride without worrying about temperature spikes or unexpected shutdowns. The Mercury 8M0113736 Water Pump Assembly is exactly that kind of part. It gives you the confidence to head out early, run long, and get home without a second thought, because you know the cooling system is doing its job with steady, predictable flow.

Key Features

• Complete water pump assembly designed for MerCruiser 496 Magnum, Magnum HO, 8.1S, and 8.1S HO engines
• Marine-grade construction built to withstand continuous exposure to heat, moisture, and vibration
• Includes pump housing and gaskets for a proper, secure installation
• Engineered for high-volume coolant circulation to support large-displacement V8 engines
• Tested to hold up in harsh saltwater environments
• Built to meet or exceed original Mercury Marine specifications for flow and durability

Engine & Boat Compatibility

• Fits MerCruiser 496 Magnum and 496 Magnum High Output sterndrive engines
• Fits MerCruiser 8.1S and 8.1S High Output inboard engines
• Common in performance boats, heavy cruisers, offshore hulls, wake boats, and large runabouts
• Designed for both raw-water and closed-cooling systems requiring a high-capacity pump

Performance & Practical Benefits

A good water pump should run so smoothly you barely notice it — and that’s exactly what this Mercury Marine part delivers. Once installed, you’ll see your engine settle into a steady operating temperature, even during long idle periods, slow no-wake zones, and the kind of hard acceleration that big-block engines love. The pump’s internal design moves coolant with a smooth and balanced rhythm, giving your engine the breathing room it needs to perform without overheating or surging.

You’ll also appreciate the tight, secure fit during installation. The housing seats cleanly, the gaskets lay flat, and the mounting points line up the way they’re supposed to. No wrestling, no odd angles — just a clean, confident install. And once it’s in place, the housing stands up to constant heat cycles and the unforgiving nature of saltwater. Many boaters notice quieter operation and more stable temperatures the very first time they fire up the engine with the new pump in place.

Durability is where this water pump really shines. It resists corrosion, maintains its internal clearances, and keeps coolant moving efficiently season after season. It’s the kind of upgrade that quietly transforms the reliability of your big-block MerCruiser.

Why Buy OEM

There’s no shortcut when it comes to cooling a high-output V8. Genuine Mercury Marine parts are engineered specifically for these big-block platforms — with the right materials, the right flow rates, and the kind of durability that offshore conditions demand. Aftermarket pumps might look similar, but they often fall short in long-term reliability or cooling efficiency. Choosing the 8M0113736 Water Pump means you’re protecting your investment, avoiding unnecessary overheating issues, and giving your engine the exact part it was designed to run with. It’s simply the smart move for anyone who spends real time on the water.

FAQ

Q1: Which engines does the 8M0113736 Water Pump fit?

It fits MerCruiser 496 Magnum, Magnum High Output, 8.1S, and 8.1S High Output engines.

Q2: What makes this different from aftermarket water pumps?

OEM engineering, superior marine materials, better cooling consistency, and long-term durability that generic versions rarely match.

Q3: How do I know if this is the correct replacement?

Check your engine model and serial range. If your boat is powered by a 496 Magnum or 8.1S platform, this is the intended Mercury Marine part.

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

Yes — it’s engineered to withstand the harsher conditions of saltwater while performing flawlessly in freshwater as well.

Q5: Is installation straightforward?

Most experienced boat owners or technicians find it simple. It installs as a direct-fit OEM replacement with included gaskets.