Mercury – Quicksilver 812966A7 Water Pump Base Assembly | Mercury FourStroke 30–60HP Outboards | Reinforced Nylon | 812966A7

Overview

A dependable cooling system keeps your outboard running strong and protected from heat damage. The Quicksilver 812966A7 Water Pump Base Assembly is built to restore that reliability in your Mercury FourStroke 30–60HP outboard. Whether you run an EFI 3-cylinder, a carbureted 4-cylinder, or anything in between, this OEM base assembly keeps water flowing smoothly through your engine’s cooling passages.

It’s made from reinforced nylon for toughness and heat resistance, designed to handle years of vibration, water pressure, and temperature swings. A solid pump base means consistent cooling, less wear, and peace of mind every time you start up.

Key Features

• Purpose: Replaces a worn or cracked water pump base to restore proper water circulation and prevent overheating.
• Fitment: For Mercury FourStroke outboards — 30/40HP EFI 3-cylinder, 40HP Carb 3-cylinder, 40–60HP EFI 4-cylinder, and 40–60HP Carb 4-cylinder engines.
• Construction: Made from reinforced nylon for strength, durability, and resistance to warping under heat.
• Included Components: Comes complete with pump housing, seals, and O-ring for a ready-to-install assembly.
• OEM Quality: Manufactured to meet or exceed Mercury Marine factory specifications for precise fit and reliable cooling performance.

Engine & Boat Compatibility

• Mercury FourStroke 30/40HP EFI (3-cylinder)
• Mercury FourStroke 40HP Carbureted (3-cylinder)
• Mercury FourStroke 40–60HP EFI (4-cylinder)
• Mercury FourStroke 40–60HP Carbureted (4-cylinder)
• Ideal for small fishing boats, pontoons, runabouts, and inflatables

Performance & Practical Benefits

The 812966A7 Water Pump Base Assembly forms the foundation of your outboard’s cooling system. When it’s worn or cracked, your engine can lose pressure and circulation — leading to overheating and internal wear. Replacing it with this OEM assembly restores the tight seal and proper flow path Mercury designed into your motor.

The reinforced nylon housing resists corrosion and distortion far better than older designs. With the included seals and O-ring, the entire unit installs cleanly and locks in a perfect seal for years of use. Once installed, you’ll notice better temperature stability, more reliable cooling at idle, and long-term confidence in your motor’s performance.

Why Buy OEM

Mercury’s OEM cooling components are made to match your engine’s original tolerances and materials. Aftermarket bases often use lower-grade plastics that can soften under heat or leak around seals. This genuine Quicksilver assembly ensures the pump’s geometry, fit, and flow remain exactly as intended.

With OEM, you’re not just replacing a part — you’re maintaining your engine’s designed efficiency and longevity. It’s the difference between a quick fix and a lasting solution that protects your investment.

FAQ

Q1: Which engines use the Quicksilver 812966A7 base assembly?
A: It fits Mercury FourStroke 30–60HP outboards, including 3- and 4-cylinder EFI and carbureted models.

Q2: What’s included in the package?
A: The assembly includes the water pump housing, seals, and O-ring, ready for installation.

Q3: What material is it made from?
A: It’s made from reinforced nylon, chosen for its strength, corrosion resistance, and heat stability.

Q4: How often should the pump base be inspected?
A: Inspect it during impeller replacement or any cooling system service — usually every 2–3 years.

Q5: Is it easy to install?
A: Yes. With basic tools and your service manual, the replacement process is straightforward for most boat owners.