Exhaust Water Shutter – Fits MerCruiser V6 & V8 Marine Engines (Replaces 807166A1)
Exhaust Water Shutter – Fits MerCruiser V6 & V8 Marine Engines (Replaces 807166A1) is backordered and will ship as soon as it is back in stock.
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Exhaust Water Shutter – Fits MerCruiser V6 & V8 Marine Engines ...
Exhaust Water Shutter – Fits MerCruiser V6 & V8 Marine Engines (Replaces 807166A1) is backordered and will ship as soon as it is back in stock.
Product Details
This Exhaust Water Shutter – Fits MerCruiser V6 & V8 Marine Engines (Replaces 807166A1) is designed to prevent water from entering the engine through the exhaust system. It is compatible with a wide range of MerCruiser stern drive engines from 1996 and newer, including 4.3L V6, 5.0L, 5.7L, 6.2L, 7.4L, and 8.2L V8 models that use a 4-inch Y-pipe exhaust system.
This component is a direct replacement for Mercury/MerCruiser part number 807166A1.
- Installs in the Y-pipe exhaust system.
- Constructed from durable rubber with an internal steel rod for structural integrity.
- Two shutters are required per engine for a complete installation.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Mercury/MerCruiser | 807166A1 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
This is the updated "clapper" design for newer Y-pipes. For older 1982-1995 engines, use the 807166A3 model instead, which includes a carrier to fit the older Y-pipe design.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. |
|---|---|---|---|---|---|
| MerCruiser | 4.3L V6 | 4.3L | 4-Stroke | 1996–Up | 807166A1 |
| MerCruiser | 5.0L V8 | 5.0L | 4-Stroke | 1996–Up | 807166A1 |
| MerCruiser | 5.7L V8 | 5.7L | 4-Stroke | 1996–Up | 807166A1 |
| MerCruiser | 6.2L V8 | 6.2L | 4-Stroke | 1996–Up | 807166A1 |
| MerCruiser | 7.4L V8 | 7.4L | 4-Stroke | 1996–Up | 807166A1 |
| MerCruiser | 8.2L V8 | 8.2L | 4-Stroke | 1996–Up | 807166A1 |
Technical Specs
- Product Type
- Exhaust Water Shutter / Flapper
- Installation
- Y-pipe exhaust system
- Fuel Type
- Gasoline
- Connection
- Fits into Y-pipe exhaust port
- Housing Material
- Rubber with internal steel rod
- Dimensions
- 6" (152.4 mm) Long x 2.5" (63.5 mm) Wide
- Fitting Type
- Drop-in with retaining plugs
- Other Technical Attributes
- Two required per engine
What’s in the Box
- 2 x Exhaust Water Shutter (807166A1)
Installation Notes
- Disconnect the boat's battery for safety.
- Gain access to the engine's exhaust Y-pipe, which may require removing the exhaust elbow/riser.
- Carefully remove the old, worn-out water shutters from the Y-pipe ports. Note their orientation.
- Thoroughly clean the shutter housing area inside the Y-pipe to remove any debris or old rubber fragments.
- Insert the new water shutters into the designated ports, ensuring they are correctly oriented to open with exhaust pressure and close against backflow.
- Confirm the shutters move freely and seat properly.
- Reinstall any components that were removed to access the Y-pipe.
- Reconnect the battery and test the engine at idle to check for proper exhaust flow and listen for any unusual noises.
Troubleshooting & FAQ
How do I know if this shutter fits my engine?
This part fits MerCruiser V6 and V8 engines from 1996 and newer with a 4" Y-pipe exhaust system. Please review the compatibility table and engine models on this page to confirm your specific application. It is not for older engines (pre-1996).
What’s the difference between this 807166A1 and the 807166A3 model?
This part (807166A1) is the updated "clapper" style shutter for 1996 and newer Y-pipes. The older 807166A3 is a different design that includes a carrier for pre-1996 (1982-1995) Y-pipe designs. The two are not interchangeable.
What are the signs of a failing water shutter?
Common symptoms include a rattling or clanking noise from the exhaust at idle, engine overheating at low speeds, and in severe cases, water ingestion into the engine cylinders, which can cause catastrophic failure. If you hear a distinct rattle that goes away with a slight increase in RPM, your shutters are likely worn or broken.
Why are two shutters included in the package?
V6 and V8 MerCruiser engines require two shutters—one for each exhaust port on the Y-pipe. It is critical to replace both at the same time to ensure balanced exhaust flow and prevent premature failure of an older, non-replaced shutter.
What is the purpose of an exhaust water shutter?
The shutter acts as a one-way valve, allowing exhaust gases to exit while preventing water from flowing back into the engine. This is especially important when the boat is decelerating quickly, in reverse, or in rough seas, as these situations can force water up the exhaust pipe.
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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