Exhaust Water Shutter Kit – Fits MerCruiser V6/V8 (Replaces 807166A1, 807166A2, 807166A3)
Exhaust Water Shutter Kit – Fits MerCruiser V6/V8 (Replaces 807166A1, 807166A2, 807166A3) is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
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Exhaust Water Shutter Kit – Fits MerCruiser V6/V8 (Replaces 807166A...
Exhaust Water Shutter Kit – Fits MerCruiser V6/V8 (Replaces 807166A1, 807166A2, 807166A3) is backordered and will ship as soon as it is back in stock.
Product Details
This Exhaust Water Shutter Kit is designed to prevent water from flowing back into the engine through the exhaust system. It is a direct-fit replacement for MerCruiser V6 and V8 sterndrive engines (1982–1999) that use a 4-inch exhaust system, ensuring protection when the engine is off or at low RPMs.
This kit serves as a direct interchange for Mercury/MerCruiser part numbers 807166A1, 807166A2, 807166A3, 14348A1, and 32-08303, as well as Sierra 18-2732-9 and 18-2733.
- Installs in the exhaust Y-pipe between the upper and lower bellows.
- Functions as a flexible check valve to block water reversion.
- Made from durable rubber/composite materials to withstand the marine environment.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Mercury/MerCruiser | 807166A1, 807166A2, 807166A3, 14348A1, 32-08303 |
| Sierra | 18-2732-9, 18-2733 |
| Copkingo/Soxa | 807166A1/A2/A3 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| MerCruiser | V6 (229 CID) | 175-205 | 4-Stroke | 1982–1995 | 807166A3 | Old style Y-pipe |
| MerCruiser | V6 (262 CID/4.3L) | 175-205 | 4-Stroke | 1983–1995 | 807166A3 | Old style Y-pipe |
| MerCruiser | V6 (262 CID/4.3L) | 175-205 | 4-Stroke | 1996–1999 | 807166A1/807166A2 | New style Y-pipe; A2 for batwing manifolds |
| MerCruiser | V8 (305 CID/5.0L) | 185-260 | 4-Stroke | 1983–1995 | 807166A3 | Old style Y-pipe |
| MerCruiser | V8 (350 CID/5.7L) | 190-330 | 4-Stroke | 1983–1995 | 807166A3 | Old style Y-pipe |
| MerCruiser | V8 (305/350/377 CID) | 190-330 | 4-Stroke | 1996–1999 | 807166A1 | New style Y-pipe |
| MerCruiser | V8 (454/502 CID) | 330-400 | 4-Stroke | 1983–1995 | 807166A3 | Old style Y-pipe |
| MerCruiser | V8 (454/502 CID) | 330-400 | 4-Stroke | 1996–1999 | 807166A1 | New style Y-pipe |
| MerCruiser | Alpha One | - | - | 1983–1995 | 807166A3 | Old style Y-pipe |
| MerCruiser | Alpha One Gen 2 | - | - | 1991–1999 | 807166A1 | New style Y-pipe |
| MerCruiser | Bravo | - | - | 1988–1999 | 807166A1 | New style Y-pipe |
Technical Specs
- Product Type
- Exhaust Water Shutter Kit
- Installation
- Y-Pipe Mounting
- Fuel Type
- Gasoline
- Connection
- Exhaust Pipe Mounting
- Housing Material
- Rubber/Composite
- Housing Color
- Black
- Fitting Type
- 4" Exhaust System
- Other Technical Attributes
- Acts as a flexible check valve to prevent water backflow into engine
What’s in the Box
- 2 x Water Shutter Flapper (replaces 807166A1, 807166A2, or 807166A3 depending on application)
Installation Notes
These water shutters are installed inside the exhaust Y-pipe assembly, positioned between the upper exhaust tube bellows (e.g., 32-44348T) and the lower exhaust tube bellows (e.g., 32-14358T). Their purpose is to act as a one-way valve, allowing exhaust to pass while preventing water from traveling up the exhaust pipe and into the engine, particularly when at idle, decelerating, or turned off.
Troubleshooting & FAQ
How do I know which shutter part number is right for my engine?
The correct shutter depends on your engine model year and Y-pipe design. 807166A3 is for older style Y-pipes (1982–1995). 807166A1 is for newer style Y-pipes (1996 and later). 807166A2 is specifically for V6 engines from 1996-1999 with "batwing" style exhaust manifolds. Always verify your engine's specific configuration.
What are the signs of a failing exhaust water shutter?
Symptoms of a worn or broken water shutter include a distinct rattling noise from the exhaust at idle, difficulty starting, or in severe cases, water ingestion into the engine cylinders (hydrolock), which can cause catastrophic engine damage.
Is this the old single-plate or the newer 2-piece "clapper" design?
This kit uses the modern 2-piece "clapper" design. Mercury/MerCruiser updated the original single-plate shutter design around 1996 because the old style could fail and allow water into the engine. This newer design is more reliable and durable.
What is the main function of this part?
The exhaust water shutter acts as a check valve to stop lake or sea water from flowing back up the exhaust system into the engine's cylinders when the engine is not running or at very low RPMs.
Is any special hardware included or required for installation?
The 807166A3 shutter for older Y-pipes typically includes a carrier to adapt it. For other versions, mounting hardware is generally not required as they fit into the existing assembly. However, always check the contents of your specific kit upon arrival.
OEM vs. Aftermarket?
This listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.
Shipping speed & cost?
We ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.
Warranty & returns?
Covered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused & in original condition). See our policy page or reach out for instructions.
Safety & Important Info
- Verify images/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.
- This is an aftermarket replacement, not an OEM component.
- Professional installation is recommended for safety and performance.
About Sea Sierra
- Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.
- Fast Global Fulfillment — Free standard delivery to most regions in 5–15 days.
- Manufacturer-Direct Value — Fair pricing without compromising on materials or QC.
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