Mercury – Heavy Duty Sea Water Pump Impeller Repair Kit | MerCruiser 4.5L & 6.2L | Composite & Elastomer | 8M0137220

Overview

There’s a certain calm that settles over you when you know your cooling system is ready for whatever the day brings. It’s the kind of confidence that comes from installing a part built exactly for the engine you trust. With the Mercury 8M0137220 Heavy Duty Sea Water Pump Impeller Repair Kit, you’ll feel that same sense of security—whether you’re easing out of the no-wake zone or pushing the throttle a bit as the water flattens out. This isn’t just another maintenance item. It’s one of those small but essential components that keeps your engine running cool, steady, and protected through long seasons on the water.

Key Features

• Complete heavy-duty impeller repair kit engineered for durability
• Includes replacement impeller, over-molded inner wear plate, rear wear plate, and housing gasket
• Designed for higher flow rates and consistent cooling performance
• Impeller elastomers provide excellent flexibility across wide temperature swings
• Built to Mercury Marine OEM specifications for MerCruiser 4.5L and 6.2L engines

Engine & Boat Compatibility

• Fits select 4.5L MerCruiser V6 engines (serial number 2A531162 and below)
• Fits select 6.2L MerCruiser V8 sterndrive engines (serial number limits apply)
• Fits compatible inboard and TowSport inboard models below listed serial ranges
• Commonly used on runabouts, cruisers, tow boats, and sport boats powered by Mercury sterndrive systems

Performance & Practical Benefits

When you install this heavy-duty kit, you’re not just swapping an old impeller—you’re restoring the engine’s heartbeat. A cooling system that moves water smoothly makes the whole boat feel different. Temperatures stay steady. Acceleration feels clean. You’re not listening for trouble. You’re simply enjoying the ride.

The reinforced wear plates add longevity and help protect the pump housing from debris and sand that inevitably work their way into a raw-water system. The impeller’s elastomer blend grips the water efficiently without feeling brittle, even after hot-running days or early-spring cold starts. Everything fits tight, seals properly, and allows the cooling system to deliver the steady flow the engine was designed to rely on.

This is one of those Mercury Marine parts that gives you genuine peace of mind every time you trim down and get on plane.

Why Buy OEM

Choosing an OEM Mercury Marine part isn’t about brand loyalty—it’s about practicality. When you’re dealing with something as critical as cooling flow, the difference between “almost right” and “exactly right” matters. This kit is engineered around the precise tolerances of your MerCruiser pump housing. It’s tested for long-term reliability, and it installs cleanly with no guesswork.

Aftermarket parts may be cheaper up front, but they rarely match the fit, material consistency, or durability of a true Mercury component. With OEM, you’ll get longer service intervals, consistent performance, and far fewer headaches. It’s the smarter choice for anyone who’d rather spend their weekends on the water instead of troubleshooting in the driveway.

FAQ

Q1: Which Mercury engines does the Heavy Duty Sea Water Pump Impeller Kit fit?

It fits select 4.5L and 6.2L MerCruiser V6 and V8 engines within the specified serial number ranges.

Q2: What makes this kit different from aftermarket options?

You’re getting Mercury-tested elastomers, wear plates, and fitment precision that match the original pump housing exactly.

Q3: How do I confirm it’s the correct kit for my engine?

Check your serial number against the listed ranges in your owner’s manual or engine data tag.

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

Absolutely—its materials are built for harsh marine environments.

Q5: Is installation straightforward?

For most owners who’ve serviced seawater pumps before, yes. Otherwise, a technician can handle it quickly.