Mercury – Water Pump Gasket | Cooling System Service | Marine Composite Seal | 8M0090319

Overview

If you’ve been on the water long enough, you know that an engine’s cooling system is one of those quiet, dependable lifelines you rarely think about—until something goes wrong. A steady stream from the telltale, a smooth idle after a long run, that comforting sense that your motor is staying cool even when the day gets hot… that’s the kind of peace a well-sealed water pump delivers. The Mercury 8M0090319 Water Pump Gasket plays a surprisingly important role in that consistency. It’s a small, simple component, but when you’re miles from the dock, parts like this are why you can trust your engine to stay steady and dependable.

Key Features

• Precision water pump gasket designed to seal the cooling system housing
• Marine-grade composite material built to handle heat, moisture, and vibration
• Provides a tight, secure seal when replacing or servicing water pump impellers
• Compatible with various Mercury and Mariner two-stroke outboards (90–200HP)
• Fits select MerCruiser sterndrive cooling systems
• Simple installation with standard shop tools

Engine & Boat Compatibility

• Fits Mercury and Mariner two-stroke outboards ranging from 90HP to 200HP
• Compatible with select MerCruiser sterndrives using this specific gasket style
• Common on center consoles, fishing boats, pontoons, classic two-stroke rigs, and sterndrive-powered cruisers
• Ideal for engines requiring a fresh gasket during routine water pump or impeller service

Performance & Practical Benefits

A gasket might seem like a small part, but anyone who has serviced a water pump knows how crucial it is. When the gasket seals properly, water flows exactly where it should—tight, steady, and under the right pressure. That means your impeller can work efficiently, your engine stays cool, and you avoid overheating issues that can ruin a weekend or worse.

The Mercury 8M0090319 gasket seats cleanly and feels secure once compressed. It doesn’t twist or fold like cheaper aftermarket seals, and the material holds up well under repeated heat cycles. Whether you’re replacing an impeller as part of annual maintenance or rebuilding a pump after noticing reduced water flow, a fresh OEM gasket gives you that “confident” feeling when you bolt everything back together.

In real-world use, you’ll notice smoother cooling performance and steady water pressure. The engine warms up properly, maintains temperature under load, and won’t surprise you with sudden temperature swings. It’s the sort of upgrade you don’t hear—but you absolutely feel when the boat runs cooler and more predictably.

Why Buy OEM

Cooling system seals need to be precise. A slightly off-center fit or a gasket made from low-quality materials can lead to leaks, low water pressure, or overheating. With a genuine Mercury Marine part, you know the gasket sits exactly where the engineers intended. It compresses evenly, resists swelling and breakdown, and lasts longer than generic alternatives. When it comes to a system as important as your water pump, buying OEM isn’t just wise—it’s the only choice that truly protects your engine.

FAQ

Q1: Which engines does the 8M0090319 Water Pump Gasket fit?

It fits select MerCruiser sterndrives and Mercury/Mariner two-stroke outboards between 90 and 200 horsepower.

Q2: What makes this gasket better than aftermarket options?

OEM gaskets use marine-grade material, offer exact fitment, and maintain a proper seal under heat and vibration.

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

Match your engine model and consult your owner’s manual for the correct Mercury Marine part number.

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

Yes. Its composite material resists corrosion, moisture, and mineral exposure.

Q5: Is installation straightforward?

Very. Most boaters can replace it during an impeller service using common hand tools.