Water Shutter Kit – Fits MerCruiser 3.0-4.2L Sterndrive & Inboard (Replaces 807166A3)

Water Shutter Kit – Fits MerCruiser 3.0-4.2L Sterndrive & Inboard (Replaces 807166A3)

This water shutter kit is designed for MerCruiser 3.0L to 4.2L inline sterndrive and inboard engines manufactured between 1994 and 1997. It is specifically engineered to fit D3.0L VM 183 I/L5, D3.6L VM 219 I/L6, and D4.2L/220 IDI VM 254 I/L6 models, serving as a crucial component to prevent water from entering the engine through the exhaust system.

This kit is a direct replacement for several OEM and aftermarket part numbers, ensuring a precise fit and reliable performance. Its durable, corrosion-resistant construction is built to withstand harsh marine environments.

• Direct Installation: Fits into the Y-pipe of the MerCruiser exhaust system.
• Prevents Water Ingestion: Acts as a check valve to protect your engine from water backflow.
• Complete Kit: Includes 2 x water shutters for a full replacement.

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.

MerCruiser Sterndrive Models

MerCruiser Inboard Models

Technical Specifications

Package Contents

• 2 x Water Shutters (Replaces OEM 807166A3)

Installation Guide

Installation should be performed by a qualified marine mechanic. The following is a general guide:

1. Safety First: Disconnect the boat’s battery and ensure the engine is cool before starting.
2. Access the Exhaust: Locate and access the exhaust Y-pipe where the sterndrive or inboard exhaust connects.
3. Remove Old Shutters: Carefully remove the old, worn water shutters from the exhaust housing. They may be brittle.
4. Clean Housing: Thoroughly clean the inside of the housing to remove any old material or debris.
5. Install New Shutters: Insert the new water shutters, ensuring they are correctly oriented and seated properly.
6. Reassemble: Reassemble all exhaust components in the reverse order of disassembly.
7. Final Check: Reconnect the battery. Once the boat is in the water, start the engine and carefully check for any exhaust or water leaks.

Troubleshooting & FAQ

How do I confirm this fits my engine?
This kit is designed for a specific range of MerCruiser 3.0L, 3.6L, and 4.2L inline engines from 1994-1997. The most reliable way to confirm fitment is to match your original part number to one of the cross-references listed, such as MerCruiser 807166A3 or Sierra 18-2732-9. Also, verify your engine model and serial number against the compatibility tables.

What are the signs of a failing water shutter?
A common sign of failure is water entering the engine cylinders through the exhaust, which can cause starting issues, hydrostatic lock, or a distinct knocking sound. You may also find broken pieces of the old shutter in the exhaust system during inspection.

How often should I replace my water shutters?
Water shutters are a wear item and should be inspected regularly during routine maintenance. Replacement intervals depend on usage (freshwater vs. saltwater) and operating conditions. It is recommended to replace them if they appear cracked, brittle, or damaged.

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.