Exhaust Water Shutter (Flapper) – Fits MerCruiser 2.5L, 3.0L, 3.7L Engines (Replaces 60930, 25-43809)

Exhaust Water Shutter (Flapper) – Fits MerCruiser 2.5L, 3.0L, 3.7L Engines

This exhaust water shutter, or flapper, is designed for MerCruiser stern drives equipped with 2.5L, 3.0L, and 3.7L inline 4-cylinder engines from various model years. It functions as a critical one-way valve within the exhaust system, preventing water from flowing back into the engine cylinders.

This part is a direct replacement for Mercury-MerCruiser part numbers 60930, 25-43809, and Sierra 18-2727.

• Designed as a direct-fit replacement for straightforward installation.
• Made from durable rubber to withstand the marine environment.
• Includes grommets required for proper installation.

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 with Grommets (Replaces 60930/25-43809)

Installation Guide

1. Safety First: Ensure the engine is completely cool and disconnect the battery before beginning work.
2. Locate the Exhaust: Identify the exhaust Y-pipe where the water shutter is located. Access may require removing other components.
3. Remove the Old Shutter: Carefully remove the old, worn-out water shutter and its grommets from the exhaust housing.
4. Clean the Housing: Thoroughly clean the inside of the housing to remove any residue or debris.
5. Install the New Shutter: Insert the new grommets and press the new water shutter firmly into place, ensuring it is properly seated.
6. Reassemble: Reinstall any components that were removed to gain access to the shutter.
7. Final Check: Reconnect the battery. Start the engine briefly to check for proper function and ensure there are no exhaust leaks.

Troubleshooting & FAQ

Q: How do I confirm this fits my engine?
A: The best way is to compare your original part number to the ones listed in our cross-reference table: Mercury-MerCruiser 60930, 25-43809, or Sierra 18-2727. Also, check the compatible models table and verify the part's dimensions against your old one.

Q: What are the symptoms of a failing exhaust water shutter?
A: Common signs include water ingestion into the cylinders (hydrolock), difficulty starting, a knocking sound from the exhaust area, or visible damage and cracking on the old flapper.

Q: How often should I replace the shutter?
A: Replacement interval depends on usage (freshwater vs. saltwater) and operating hours. It's good practice to inspect it annually and replace it every few seasons or at the first sign of wear, brittleness, or damage.

Q: Is this an OEM part?
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.