Mercury – Quicksilver Water Shutter | For Select MerCruiser Sterndrive Engines | 807166A1

Overview

A small part with a big job, the Mercury Marine 807166A1 Quicksilver Water Shutter helps keep water where it belongs — out of your engine. Designed for select MerCruiser sterndrive and inboard engines, this shutter sits inside the exhaust system and acts like a one-way valve. When your engine is running, it allows exhaust gases to flow freely. When it’s idling, off, or facing rough water, it swings shut to prevent backflow from following seas or wakes that could flood your cylinders. It’s a simple, reliable safeguard that protects your engine from costly damage.

Key Features

• Purpose: Prevents water from backing up into the exhaust and engine when the motor is off or idling.
• Design: Acts as a flexible check valve for exhaust systems in MerCruiser sterndrives.
• Size: Features a 2.48-inch diameter cross pin (hinge pin).
• Construction: Built from durable, heat-resistant materials that withstand exhaust heat and vibration.
• Fitment: Direct OEM replacement for consistent, reliable performance.

Engine & Boat Compatibility

• Select MerCruiser sterndrive and inboard engines (see owner’s manual or service manual for fitment details)

Performance & Real-World Benefits

The 807166A1 water shutter does one thing but does it exceptionally well — it protects your engine from backwash. If water ever gets pushed up through the exhaust system, it can flow into the cylinders, causing hydrolock or internal rust damage. This small shutter swings into action when your engine slows down or shuts off, blocking that reverse flow instantly.

Made from marine-grade materials that resist exhaust heat and saltwater exposure, it’s built to handle years of use. When it’s working properly, you won’t even notice it — but your engine will thank you every time you head back down the wake or face choppy water.

Why Choose Mercury OEM

The Quicksilver 807166A1 is a genuine Mercury Marine part, designed and tested for the exact flow rates, temperatures, and angles of MerCruiser exhaust systems. Aftermarket shutters may not seal correctly or could degrade quickly from heat exposure, putting your engine at risk.

Mercury’s OEM components are built to the same standards used in factory-installed parts — ensuring precise fit, reliable sealing, and long-lasting durability. It’s the level of protection that only the people who built your engine can truly deliver.

FAQ

Q1: What does a water shutter do?
It prevents water from flowing backward through the exhaust into the engine when idling or off.

Q2: What’s the shutter size?
It measures 2.48 inches in diameter at the hinge pin.

Q3: What engines does it fit?
It’s designed for select MerCruiser sterndrive and inboard engines — check your manual for details.

Q4: When should I replace it?
Replace it if it’s cracked, warped, or no longer sealing properly — typically during major exhaust service.

Q5: Why OEM instead of aftermarket?
Because Mercury OEM shutters are built to precise tolerances and materials that resist exhaust heat and saltwater, ensuring long-term reliability.