4-Inch Water Shutter for MerCruiser Stern Drives – Replaces OEM 807166A1
4-Inch Water Shutter for MerCruiser Stern Drives – Replaces OEM 807166A1 is backordered and will ship as soon as it is back in stock.
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4-Inch Water Shutter for MerCruiser Stern Drives – Replaces OEM 807...
4-Inch Water Shutter for MerCruiser Stern Drives – Replaces OEM 807166A1 is backordered and will ship as soon as it is back in stock.
Product Details
This aftermarket 4-inch water shutter is designed as a replacement for the MerCruiser water shutter identified by OEM part number 807166A1. It installs in the exhaust system and helps limit water backflow toward the engine when the engine is not running or operating at low RPM.
This listing is for one water shutter, not a complete exhaust, bellows, manifold, or mounting kit. Confirm that your application uses the 4-inch water-shutter design and compare the mounting arrangement with the original component before ordering.
- 4-inch water shutter for applicable MerCruiser stern-drive exhaust systems.
- Functions as an exhaust check flap to help resist water entering through the exhaust path.
- Aftermarket replacement for the OEM reference listed below.
- Designed for installation inside the applicable exhaust Y-pipe or related exhaust passage.
Part Number Information
Use the following manufacturer reference to compare your original part and verify application compatibility.
| Brand | Reference Type | Part Number |
|---|---|---|
| Mercury MerCruiser | OEM reference | 807166A1 |
Compatibility
The referenced catalog application identifies this component as a 4-inch MerCruiser water shutter. Compatibility depends on the exhaust-system design, shutter diameter, mounting points, and surrounding Y-pipe or exhaust hardware. Model name alone is not sufficient to confirm fitment.
| Manufacturer | Application | Size | OEM Reference | Fitment Notes |
|---|---|---|---|---|
| MerCruiser | Applicable stern-drive exhaust systems | 4-inch water shutter | 807166A1 | Verify the original shutter size and mounting geometry before purchase. |
Technical Specifications
- Product Type
- Water shutter
- Replacement Type
- Aftermarket replacement
- Nominal Size
- 4 inches
- Installation Location
- Applicable exhaust Y-pipe or exhaust passage
- Primary Function
- Helps restrict water backflow through the exhaust system when the engine is stopped or operating at low RPM
- OEM Reference
- 807166A1
What’s in the Box
- 1 x 4-inch water shutter
Gaskets, clamps, bellows, Y-pipes, adapters, and other installation hardware are not included unless specifically shown or stated in the product offer.
Installation Notes
Installation requires access to the applicable exhaust passage or Y-pipe and may require removal of surrounding exhaust components. Remove the old shutter carefully, clean the mounting area, and compare the replacement with the original before installation. Seat the shutter correctly in its mounting points and confirm that it moves as intended without interference. Reassemble all removed components according to the engine and stern-drive service instructions, then inspect for exhaust leaks before returning the boat to service.
Because exhaust-system access and removal procedures vary by installation, professional marine-service installation is recommended when the correct procedure is not known.
Troubleshooting & FAQ
How do I verify that this water shutter fits?
Confirm that your original component is a 4-inch MerCruiser water shutter and that it uses the same mounting arrangement. Compare the original part, exhaust passage, and Y-pipe geometry with the product information before ordering. If the diameter or mounting design differs, this replacement may not be suitable.
What is the function of a water shutter?
A water shutter, also called an exhaust flapper in some applications, helps reduce the risk of water traveling backward through the exhaust system and toward the engine when the engine is stopped or operating at low RPM.
What are common signs of a worn water shutter?
Possible signs include rattling from the exhaust area, damaged or missing rubber material, visible deterioration, or pieces of the shutter found in the exhaust. A damaged shutter should be inspected and replaced promptly.
How often should the water shutter be inspected?
Inspect it whenever the surrounding exhaust components are serviced and during routine seasonal maintenance. Replace it if it is cracked, brittle, distorted, loose, or missing material.
Is this an OEM component?
No. This listing is for an aftermarket replacement corresponding to OEM reference 807166A1.
Does the package include a complete installation kit?
No. The package contains one 4-inch water shutter. Additional exhaust hardware, gaskets, clamps, bellows, or adapters are not included unless separately stated in the offer.
Safety & Important Information
- Verify the 4-inch size, original part design, and mounting arrangement before ordering.
- Do not rely on engine model or horsepower alone to confirm fitment.
- Inspect all related exhaust components while the shutter is accessible.
- This is an aftermarket replacement, not an OEM component.
- Professional installation is recommended when exhaust-system access or reassembly is uncertain.
About Sea Sierra
- Marine Replacement Parts — We supply replacement components for common marine service and repair applications.
- Application-Focused Listings — Product information is organized around part references and physical fitment details to support more accurate ordering.
- Customer Support — Contact support with your original part details and application information if you need help comparing components.
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