2-Piece Exhaust Water Shutter Set for MerCruiser Stern Drive Applications – Replaces 807166A3
2-Piece Exhaust Water Shutter Set for MerCruiser Stern Drive Applications – Replaces 807166A3 is backordered and will ship as soon as it is back in stock.
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2-Piece Exhaust Water Shutter Set for MerCruiser Stern Drive Applic...
2-Piece Exhaust Water Shutter Set for MerCruiser Stern Drive Applications – Replaces 807166A3 is backordered and will ship as soon as it is back in stock.
Product Details
This 2-piece exhaust water shutter set is designed for MerCruiser stern drive and outdrive applications. The flexible shutter acts as a check valve in the exhaust system, helping prevent water from returning through the exhaust passage toward the engine.
The shutters use a 2.50-inch cross-pin diameter and are intended for installation in the matching exhaust water-shutter location. Always compare the original shutter and cross-pin dimensions before ordering.
- Two exhaust water shutters supplied as one pair.
- Flexible check-valve design helps limit water return through the exhaust.
- For MerCruiser stern drive and outdrive applications.
- Aftermarket replacement for the applicable original exhaust water shutter.
Part Number References
These references are provided for identification and cross-reference purposes. Confirm the original part, application, and dimensions before installation.
| Brand or Reference | Part Number |
|---|---|
| Mercury Marine reference | 807166A3 |
| Sierra Marine | 18-2732 |
| Sierra Marine | 18-2732-9 |
| Mallory Marine | 9-42802 |
| GLM | 89170 |
Application Information
This product is listed for MerCruiser stern drive and outdrive water-shutter applications. The available product information does not establish a complete model, horsepower, year, serial-number, or fuel-type range. Use the reference number and dimensional check below to confirm compatibility.
| Application | Details |
|---|---|
| Engine or drive brand | MerCruiser |
| Drive location | Stern drive / outdrive |
| Component | Exhaust water shutter / flapper valve |
| Cross-pin diameter | 2.50 inches |
| Reference replacement number | 807166A3 |
Technical Specifications
- Product Type
- Exhaust water shutter pair
- Function
- Flexible check valve that helps stop water from returning up the exhaust system toward the engine
- Quantity
- 2 shutters
- Installation Location
- Matching exhaust water-shutter position in the stern drive or outdrive exhaust system
- Cross-Pin Diameter
- 2.50 inches
- Part Type
- Aftermarket replacement
What’s in the Box
- 2 x Exhaust water shutter assemblies
Note: Mounting grommets and other installation hardware are not identified as included in the company product record.
Installation Notes
- Disconnect the battery and allow the engine and exhaust system to cool completely.
- Locate the exhaust water-shutter position in the stern drive or outdrive exhaust assembly.
- Remove the worn shutters carefully, avoiding damage to the surrounding exhaust components.
- Clean the mounting area and inspect the cross-pin holes and surrounding parts for corrosion, damage, or distortion.
- Compare the replacement shutters with the original parts, including the 2.50-inch cross-pin dimension.
- Install the two shutters in the correct orientation and confirm that each shutter moves freely without binding.
- Reassemble the exhaust components according to the engine or drive manufacturer’s service procedure.
- After installation, run the engine according to the applicable service procedure and check for abnormal exhaust noise, water leaks, or restricted movement.
Troubleshooting & FAQ
How do I confirm that this water shutter fits?
Confirm that your application is a MerCruiser stern drive or outdrive exhaust water-shutter application, then compare the original part, the 807166A3 reference, and the 2.50-inch cross-pin diameter. Model, year, serial-number, and drive-specific fitment should be verified before ordering.
What does the exhaust water shutter do?
The flexible shutter acts as a check valve in the exhaust system. Its purpose is to help prevent water from traveling back through the exhaust passage toward the engine.
Is this sold as one shutter or a pair?
This product is supplied as a pair of two exhaust water shutters. It is not listed as a complete hardware kit, and mounting grommets are not identified as included.
Is this an OEM component?
No. This is an aftermarket replacement part. The listed manufacturer references are provided for identification and compatibility cross-reference only.
Should I replace both shutters at the same time?
Because this product is supplied as a pair, replacing both matching shutters together can help maintain consistent operation. Inspect the surrounding exhaust components and mounting points during installation.
Safety & Important Information
- Verify the original part number, application, and 2.50-inch cross-pin dimension before purchase.
- Do not rely on engine displacement, horsepower, year, or brand alone to determine fitment.
- Inspect the exhaust system for corrosion or damage before installing replacement shutters.
- Professional installation is recommended when access to the exhaust assembly is limited or when water-ingestion risk is involved.
- This is an aftermarket replacement, not an OEM component.
About Sea Sierra
- Marine Replacement Parts — We supply replacement components for marine engine and drive systems.
- Application-Focused Information — Product references and dimensions are provided to support compatibility checks.
- Practical Replacement Solutions — Designed to help restore the intended function of serviceable marine components.
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