Mercury – Water Pump Impeller | 15–25HP Outboard Cooling System | Marine Elastomer Construction | 8M0204712

Overview

There’s a certain comfort in knowing your outboard is staying cool no matter what kind of water you’re running through. When you’re pushing across a windy bay or idling down a narrow creek, you want that steady cooling flow you don’t have to think twice about. This Mercury Marine part delivers exactly that kind of peace of mind. It’s one of those hidden components that quietly carries the day, keeping your engine protected so you can focus on the moments that matter the sound of the water, the pull of the tide, the simple joy of being out there.

Key Features.

• Designed to pump cooling water through the engine for consistent temperature control
• Built with marine-grade elastomers for flexibility across wide temperature ranges
• Center insert is reinforced to resist tearing and ensure long-term performance
• Manufactured to Mercury Marine part number 8M0204712 specifications
• Optimized for durability throughout the boating season
• Meets OEM requirements for proper fit and cooling efficiency

Engine & Boat Compatibility

• Fits Mercury and Mariner fifteen to twenty-five horsepower outboards
• Compatible with four-stroke platforms requiring this impeller design
• Common on small fishing boats, tenders, jon boats, and lightweight utility craft
• Ideal for kayakers and anglers using small outboards for shallow or tight-water runs

Performance & Practical Benefits

Cooling performance is something you feel throughout the entire day on the water. A strong impeller keeps the temperature steady, the motor running smooth, and the stress level low. This impeller’s elastomer construction gives it the flexibility to perform in both early-season cold and peak-summer heat, which makes a noticeable difference in how reliably water flows through the system.

The reinforced center helps keep the blades secure, even when you’re trimming up in shallow water or running through debris-filled channels. Installation feels straightforward — the impeller seats firmly into the housing with a snug, secure fit that makes you confident the cooling stream will stay consistent. Once installed, you’ll notice the engine holds temperature better, idles more predictably, and responds with a clean, steady tone that signals everything beneath the cowling is working together the way Mercury intended.

Why Buy OEM

A water pump impeller isn’t a part you want to gamble on. Using a genuine Mercury Marine part means you’re running a component engineered to protect one of the most important systems in your outboard. Aftermarket impellers often vary in material stiffness or blade design, which can lead to inconsistent cooling or premature failure. That’s not something you want to discover twenty minutes from the ramp.

OEM parts fit right the first time, last longer, and give you the kind of reliable performance that keeps your engine healthy season after season. It’s the kind of advice you’d hear from any experienced boater leaning against the dock: when it comes to cooling, go with the part Mercury built for your engine.

FAQ

Q1: Which Mercury engines does the Water Pump Impeller 8M0204712 fit?

It fits Mercury and Mariner fifteen to twenty-five horsepower outboards, particularly four-stroke models using this impeller style.

Q2: What makes this impeller better than aftermarket options?

The elastomer material, reinforced center, and precise blade design match Mercury’s original cooling specifications.

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

Check your outboard’s model and match the part number. If your manual lists 8M0204712, or you have a fifteen to twenty-five horsepower platform requiring this impeller size, you’re set.

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

Absolutely. The materials are designed for marine environments and resist swelling, cracking, and heat-related wear.

Q5: Is installation straightforward for most boat owners?

Yes — most owners comfortable with basic outboard maintenance can replace the impeller using common hand tools.