Water Exhaust Shutter Kit – Fits MerCruiser 4.3L V6 Engines (Replaces 807166A2)

Water Exhaust Shutter Kit – Fits MerCruiser 4.3L V6 Engines (Replaces 807166A2)

This aftermarket water exhaust shutter kit is specifically designed for MerCruiser 4.3L V6 engines equipped with 1-piece exhaust manifolds. It is engineered to fit Y-pipes (also known as bullhorns) that feature a 2.98-inch cross pin diameter, ensuring a precise and reliable installation.

This kit serves as a direct replacement for Mercury/Mercruiser part number 807166A2 and Quicksilver part number 807166A2.

• Prevents water from backflowing into the engine cylinders, protecting against hydrolock.
• Designed for installation in the exhaust Y-Pipe (Bullhorn).
• Package includes one exhaust shutter and four installation grommets.

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 Exhaust Water Shutter (807166A2)
• 4 x Grommets (807167)

Installation Guide

1. Safety First: Disconnect the boat's battery before beginning any work.
2. Access the Y-Pipe: Locate the exhaust Y-pipe (bullhorn) where the exhaust collects before exiting the transom. You may need to remove other components for access.
3. Remove the Old Shutter: Carefully remove the old, worn-out water shutter and its grommets from the Y-pipe.
4. Clean the Surface: Thoroughly clean the mounting area inside the Y-pipe, removing any debris or old rubber residue.
5. Install New Grommets: Insert the four new grommets into their designated holes in the Y-pipe.
6. Install the New Shutter: Position the new water shutter, ensuring it is correctly aligned with the cross pin. The shutter should move freely.
7. Reassemble Components: Re-install any exhaust hoses or components that were removed for access.
8. Final Checks: Reconnect the battery. Start the engine and check for any exhaust or water leaks around the service area.

Troubleshooting & FAQ

Q: How do I know if this water shutter will fit my MerCruiser engine?
A: This kit is for MerCruiser 4.3L V6 engines using a 1-piece exhaust manifold. Crucially, it fits Y-pipes (bullhorns) that have a 2.98-inch cross pin diameter. Please measure your existing setup or consult your service manual to confirm this dimension before ordering. You can also check the compatible model list on this page using your engine's serial number range.

Q: What is the purpose of the exhaust water shutter?
A: The shutter acts as a one-way valve in your exhaust system. It is critical for preventing water from flowing back up into the engine when it is off or at idle RPMs, which could cause hydrolocking—a catastrophic and costly engine failure.

Q: When should I replace the water shutter?
A: We recommend inspecting the shutter annually as part of regular maintenance. You should replace it immediately if you see any signs of cracking, brittleness, peeling, or other physical damage. A faulty shutter can lead to severe engine damage from water ingestion.

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 ISO9002-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.