Water Exhaust Shutter Kit – Fits MerCruiser Stern Drive 3.0L/3.6L/4.2L Diesel (Replaces 807166A3)

Water Exhaust Shutter Kit – Fits MerCruiser Stern Drive 3.0L/3.6L/4.2L Diesel (Replaces 807166A3)

This water exhaust shutter kit is designed for select MerCruiser Stern Drive diesel engines, including the 3.0L VM 183, 3.6L VM 219, and 4.2L VM 254 models manufactured between 1994 and 1997. It prevents water from entering the engine through the exhaust system, which is critical for engine protection.

This component is a direct replacement for MerCruiser part number 807166A3 and aftermarket parts including Sierra 18-2732, GLM 89170, and Mallory 9-42802.

• Fits oval 4" Y-pipes with round pin holes for secure mounting.
• Engineered specifically for diesel applications.
• The package includes a complete set of two water shutter assemblies.

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

• 2 x Water Shutter Assembly (Replaces 807166A3)

Installation Guide

1. Safety First: Ensure the engine is completely cool and disconnect the boat's battery before starting.
2. Locate Y-Pipe: Identify the exhaust Y-pipe on your MerCruiser engine where the exhaust shutters are located.
3. Remove Old Shutters: Carefully detach and remove the old, worn-out water shutters. Take note of their orientation.
4. Clean Surface: Thoroughly clean the inside of the Y-pipe mounting area to remove any old sealant, debris, or corrosion.
5. Install New Shutters: Insert the new water shutters, making sure they are aligned correctly with the round pin holes.
6. Verify Movement: Check that the shutters can open and close freely without binding.
7. Reassemble: Reconnect any other exhaust components that were removed.
8. Final Check: Reconnect the battery, start the engine, and inspect for any exhaust or water leaks around the Y-pipe.

Troubleshooting & FAQ

Q: How do I confirm this shutter kit fits my specific engine?
A: The surest way is to match your engine's model and serial number range to the 'Compatible Engine Models' table above. This part fits oval 4" Y-pipes with round pin holes, so visually comparing it to your existing part is also a reliable check.

Q: What are the common signs of a failed water shutter?
A: Common symptoms include a rattling noise coming from the exhaust at idle, engine overheating at low RPMs, and, in severe cases, water entering the engine cylinders (hydrolock). Prompt replacement is crucial to prevent engine damage.

Q: How often should I replace the exhaust water shutter?
A: There is no fixed replacement interval, but they should be inspected regularly for wear, cracks, or brittleness, especially if the boat is used in saltwater. We recommend checking them during routine annual service.

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.