Exhaust Water Shutter – Fits MerCruiser V6 & V8 Marine Engines (Replaces 807166A1)

Exhaust Water Shutter – Fits MerCruiser V6 & V8 Marine Engines (Replaces 807166A1)

This exhaust water shutter is designed for MerCruiser stern drives equipped with 4.3L V6, 5.0L V8, 5.7L V8, 6.2L V8, 7.4L V8, and 8.2L V8 engines manufactured from 1996 and newer. It is compatible with 4" Y-pipe exhaust systems.

This part is a direct replacement for Mercury/MerCruiser part number 807166A1. This is the updated "clapper" design for newer Y-pipes. For older engines (1982-1995), use part number 807166A3.

• Installation Method: Installs directly into the Y-pipe exhaust port.
• Durable Construction: Made from high-grade rubber with an internal steel rod for structural integrity.
• Complete Set: Includes two shutters, sufficient for one engine.

Compatible Engine Models

Confirm your engine model/year in the table below.

Technical Specifications

Package Contents

• 2 x Exhaust Water Shutter (Replaces 807166A1)

Installation Guide

1. Ensure the engine is turned off and has completely cooled down before starting.
2. Locate and access the Y-pipe assembly at the rear of the engine.
3. Carefully remove the old, worn-out water shutters from the Y-pipe exhaust ports.
4. Clean the inside of the ports to remove any debris or corrosion.
5. Insert the new water shutters, ensuring they are oriented correctly and seated properly.
6. Confirm both shutters (two per engine) are securely in place.

Troubleshooting & FAQ

How do I know if this water shutter will fit my engine?
This shutter fits MerCruiser V6 and V8 engines (4.3L to 8.2L) from 1996 and newer with a 4" Y-pipe exhaust system. It replaces OEM part 807166A1. For engines from 1982-1995, you will need the 807166A3 model instead. Please check the compatibility table to be sure.

What is the function of an exhaust water shutter?
The exhaust water shutter, or "flapper," is a critical component that prevents water from flowing back up the exhaust system and into the engine cylinders when the engine is off or idling. This prevents severe "water ingestion" engine damage.

What are the signs of a failing water shutter?
Common signs include a distinct rattling noise from the exhaust at idle, visible cracks or damage to the rubber, or pieces of the old shutter being expelled from the exhaust. It's recommended to inspect them annually as part of regular maintenance.

How many shutters do I need?
Two shutters are required per engine. This package conveniently includes a set of two.

OEM vs. Aftermarket?
This listing is an aftermarket replacement part (not an OEM component). We build to OEM specifications using comparable-grade materials. Production is done in an ISO9002-certified facility, and each batch is inspected for consistent performance.

How fast do you ship and how much does it cost?
We offer fast global shipping—typically 5–15 days worldwide—and standard shipping is free. Expedited options are available at checkout depending on your location.

What is your warranty and return policy?
This product includes a 1-year warranty against manufacturing defects under normal use. If something goes wrong, contact our support team with your order details. Returns are accepted within our standard return window (unused & in original condition); please see our policy page or reach out for instructions.

Important Notes

• Verify that the product images and specifications match your original part. If discrepancies exist—even if your model is listed—do not proceed with the purchase.
• This product is an aftermarket replacement part and is not an OEM component.
• Professional installation is recommended to ensure safety and optimal performance.

Why Choose JLM MARINE?

• Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
• Fast Global Shipping: Free delivery worldwide in 5–15 days.
• Direct from Manufacturer: Competitive pricing without compromising quality.