Water Shutter Kit – Fits MerCruiser Stern Drives (Replaces 807166A1)

Water Shutter Kit – Fits MerCruiser Stern Drives (Replaces 807166A1)

This water shutter kit is designed for MerCruiser V6 and V8 stern drive engines (262-454 CID) from 1998 and newer that are equipped with oval 4-inch Y-pipes and use rectangular pin holes for mounting.

It serves as a direct replacement for Mercury and Mercruiser part number 807166A1, preventing water from washing back into the engine through the exhaust system.

• Installation: Mounts directly inside the exhaust Y-pipe.
• Design: Features a durable 2-piece rubber clapper design with a metal rod.
• Compatibility: Specifically fits 4-inch oval Y-pipes with rectangular pin holes.

Part Number Cross-Reference

Use this table to confirm equivalent part numbers across OEM and aftermarket brands.

Compatible Engine Models

Confirm your engine model/year in the table below. For Mercury owners, here’s a guide to help you identify your engine’s serial/model: Mercury Serial Number Guide. You can also review exploded diagrams to verify part numbers: Mercury Parts Diagrams & Catalog.

Technical Specifications

Package Contents

• 1 x Water Shutter Kit (Replaces 807166A1)

Installation Guide

1. Ensure the engine is off and has completely cooled down before beginning.
2. Locate the exhaust Y-pipe, which is typically situated at the rear of the engine where the two exhaust manifolds converge.
3. Depending on your setup, you may need to disconnect the exhaust bellows to access the inside of the Y-pipe.
4. Carefully remove the old water shutter. Take note of its orientation and how it is secured.
5. Thoroughly clean the mounting area inside the Y-pipe to remove any debris or residue from the old shutter.
6. Insert the new water shutter, making sure the clapper component is oriented correctly to allow exhaust out while preventing water from entering.
7. Align the new shutter's pin with the rectangular holes in the Y-pipe and secure it in place.
8. Reconnect any exhaust boots or bellows that were previously removed.
9. Once installation is complete, start the engine and check for proper exhaust flow and listen for any unusual noises.

Troubleshooting & FAQ

Q: How do I know if this water shutter will fit my MerCruiser engine?

A: This kit is specifically designed for MerCruiser V6 and V8 engines made in 1998 and newer that use an oval 4-inch Y-pipe with rectangular pin holes. It directly replaces OEM part 807166A1. It is important to note this part will not fit "batwing" style single-piece V6 manifolds. Always confirm your part number and Y-pipe design before purchasing.

Q: What is the function of a water shutter?

A: A water shutter acts as a critical one-way valve in your exhaust system. It opens to allow exhaust gases to escape but closes to prevent water from flowing back up the exhaust and into the engine, especially when the boat is decelerating quickly or is stationary in the water. This protects the engine from catastrophic water damage.

Q: What are the common signs of a failed water shutter?

A: The most common symptoms of a failing water shutter include a distinct rattling sound coming from the exhaust area at idle, finding pieces of black rubber in the exhaust water, or experiencing engine overheating at idle, which can be caused by broken shutter pieces creating an exhaust blockage.

Q: OEM vs. Aftermarket?

A: 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 ISO9001-certified facility, and each batch is inspected for consistent performance.

Q: How fast do you ship and how much does it cost?

A: 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.

Q: What is your warranty and return policy?

A: 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.