Mercury – Water Pump Assembly | MerCruiser Cooling System | Aluminum & Marine Composite | 8M0113735

Overview

If you spend enough time on the water, you learn to appreciate the parts you never want to think about — the ones that quietly keep your engine running cool while you’re busy soaking in the breeze or watching the horizon roll by. A dependable water pump becomes one of those silent partners in every good day on the water. The Mercury 8M0113735 Water Pump gives you that same steady reassurance. Whether you’re cruising with family or pushing a deep-rumbling V8 toward open water, it keeps the cooling system moving the way it should so your engine stays calm, smooth, and confident.

Key Features

• Bi-directional water pump engineered for select V8 MerCruiser sterndrive engines
• Designed for General Motors-based 454 and 502 cubic-inch MerCruiser platforms
• Complete assembly includes water pump, housing, and gaskets for a proper seal
• Durable marine-grade aluminum housing and internal components built for long service life
• Precision-machined internals ensure steady coolant flow in either rotational direction
• Built to maintain consistent cooling under heavy load and extended run times

Engine & Boat Compatibility

• Fits V8 MerCruiser sterndrive engines built on General Motors 454 and 502 cubic-inch blocks
• Common in performance boats, cruisers, sport boats, and larger runabouts
• Compatible with both Alpha and Bravo-series sterndrives where these engines are installed
• Intended for freshwater and saltwater MerCruiser cooling system layouts

Performance & Practical Benefits

A water pump is one of those pieces you don’t notice until it isn’t doing its job — which is exactly why the Mercury 8M0113735 is built to feel invisible in the best possible way. Once installed, you’ll notice how steady your engine temperature stays, even during long idle periods or high-load climbs onto plane. The pump moves coolant with a smooth, balanced rhythm thanks to its bi-directional design, which keeps the system performing correctly regardless of crank rotation or application demands.

The aluminum housing feels solid in your hands during installation, and once it’s mounted, it sits tight and secure without chatter or vibration. Inside, the marine-designed impeller and passages handle heat, pressure, and long hours of operation with consistency that cheaper alternatives struggle to match. Over time, you’ll appreciate how the pump resists corrosion, holds its clearances, and maintains cooling efficiency season after season — even when you’re running in warmer waters or pushing your engine hard for extended runs.

Replacing the water pump often brings immediate improvements: quicker temperature stabilization, smoother idle, and more confidence when you’re far from the dock. It’s one of those upgrades that quietly elevates the whole boating experience.

Why Buy OEM

If you’ve ever had a cooling issue ruin a weekend, you know why this matters. Genuine Mercury Marine parts are built for the engines they serve, not just made to “fit.” The 8M0113735 Water Pump is designed to match the exact tolerances, flow requirements, and mounting geometry of your MerCruiser V8. Aftermarket pumps may look similar, but their materials and machining rarely match OEM cooling stability or long-term durability. Choosing Mercury means fewer surprises, longer service intervals, and the kind of reliability that keeps you out on the water instead of troubleshooting in the slip.

FAQ

Q1: Which engines does the 8M0113735 Water Pump fit?

It’s designed for MerCruiser V8 engines built on General Motors 454 and 502 cubic-inch platforms.

Q2: What makes this better than aftermarket alternatives?

OEM engineering, tighter machining tolerances, and marine-specific materials that hold up under heat, vibration, and long runtime hours.

Q3: How do I know if it’s the correct replacement?

Check your engine’s model and serial range. If you’re running a 454 or 502 MerCruiser, this Mercury Marine part is the intended match.

Q4: Can it be used in saltwater and freshwater?

Yes — the materials are chosen specifically for harsh marine environments.

Q5: Is installation straightforward?

Most boaters familiar with sterndrive service can install it with standard tools. It’s a direct-fit OEM replacement.