Exhaust Water Shutter Kit – Fits MerCruiser 3.0-4.2L (Replaces 807166A3)

Exhaust Water Shutter Kit – Fits MerCruiser 3.0-4.2L (Replaces 807166A3)Exhaust Water Shutter Kit Fits MerCruiser 3. 0 4. 2L (Replaces 807166A3) This exhaust water shutter kit is designed for specific MerCruiser 3. 0L, 3. 6L, and 4. 2L inboard and sterndrive engines manufactured between 1994 and 1997. It acts as a critical check valve, preventing water from flowing back up the exhaust system and into the engine. This kit is a direct replacement for the following OEM and aftermarket part numbers: Mercury MerCruiser

Exhaust Water Shutter Kit – Fits MerCruiser 3.0-4.2L (Replaces 807166A3)

This exhaust water shutter kit is designed for specific MerCruiser 3.0L, 3.6L, and 4.2L inboard and sterndrive engines manufactured between 1994 and 1997. It acts as a critical check valve, preventing water from flowing back up the exhaust system and into the engine.

This kit is a direct replacement for the following OEM and aftermarket part numbers: Mercury/MerCruiser 807166A3, Sierra 18-2732-9, GLM 89170, and Mallory 9-42802.

• Function: Acts as a flexible check valve to stop water from returning up the exhaust system to the engine.
• Installation: Designed for direct replacement of the original shutter.
• Package Contents: Includes two water shutters to service your engine.

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.

Technical Specifications

Package Contents

• 2 x Water Shutters (Replaces 807166A3)

Installation Guide

1. Safety First: Ensure the engine is completely cool and disconnect the battery before beginning work.
2. Locate Shutter Housing: Identify the exhaust Y-pipe or riser where the water shutter is located.
3. Access the Shutter: Carefully remove the exhaust hoses or elbow connected to the riser to gain access to the old shutter.
4. Remove Old Shutter: Take out the old, worn water shutter. Thoroughly clean the inside of the housing to remove any old rubber pieces or debris.
5. Install New Shutter: Insert the new shutter into the housing. Ensure it is oriented correctly to open for exhaust gases to exit while preventing water from entering.
6. Reassemble Components: Reinstall the exhaust elbow and hoses. Securely tighten all clamps and bolts to manufacturer specifications to prevent leaks.
7. Final Check: Reconnect the battery, start the engine, and carefully check for any exhaust or water leaks around the service area.

Troubleshooting & FAQ

Q: How do I confirm this fits my engine?
A: This kit is designed for MerCruiser 3.0L, 3.6L, and 4.2L engines from 1994-1997. To ensure compatibility, check your engine's model and serial number against the "Compatible Engine Models" table above. It directly replaces OEM part number 807166A3.

Q: What are the signs of a failing water shutter?
A: Common symptoms include a rattling sound from the exhaust at idle, water ingestion into the engine cylinders (which can cause hydrolock), difficulty starting, or finding visible rubber fragments in the exhaust water discharge.

Q: How often should I replace the exhaust water shutter?
A: We recommend inspecting the water shutters annually during routine maintenance. They should be replaced every 3-5 years, or immediately if you notice any signs of cracking, brittleness, or deterioration, especially for boats operated in saltwater.

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.