Water Shutter Kit – Fits MerCruiser V6, V8 (Replaces 807166A1)
Water Shutter Kit – Fits MerCruiser V6, V8 (Replaces 807166A1) is backordered and will ship as soon as it is back in stock.
Worry-free returns
Worry-free returns
Shop with confidence. If you’re not completely satisfied, eligible items may be returned within the return window, provided they are unused and in original packaging.
If the return is due to our error or a defective item, we’ll make it right.
Please contact us before returning any item.
Delivery and Shipping
Delivery and Shipping
Orders are typically processed within 1–2 business days.
U.S. orders usually arrive within 6–15 days, depending on stock location and destination.
International delivery times may vary due to customs processing.
Tracking information will be provided once your order ships.
Water Shutter Kit – Fits MerCruiser V6, V8 (Replaces 807166A1)
Water Shutter Kit – Fits MerCruiser V6, V8 (Replaces 807166A1) is backordered and will ship as soon as it is back in stock.
Product Details
This aftermarket Water Shutter Kit – Fits MerCruiser Stern Drives (Replaces 807166A1) is designed for MerCruiser V6 and V8 stern drive engines (262-454 CID) manufactured in 1998 and newer. It is specifically made for models equipped with oval 4-inch Y-pipes that use rectangular pin holes for mounting.
It serves as a direct replacement for Mercury part number 807166A1 and Mercruiser 807166A1.
- Mounts inside the exhaust Y-pipe to prevent water backflow.
- Features a durable 2-piece rubber clapper design.
- Acts as a crucial check valve to protect the engine when not running or at low RPMs.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket suppliers.
| Brand | Part Number |
|---|---|
| Mercury | 807166A1 |
| Mercruiser | 807166A1 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
| Brand | Model | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|
| MerCruiser | 5.0L MPI ALPHA/BRAVO | 4-Stroke | 1998 and newer | 807166A1 | |
| MerCruiser | 350 MAG MPI ALPHA/BRAVO | 4-Stroke | 1998 and newer | 807166A1 | |
| MerCruiser | 377 MAG MPI BRAVO | 4-Stroke | 1998 and newer | 807166A1 | |
| MerCruiser | 8.2L MAG / 8.2L MAG HO | 4-Stroke | 1998 and newer | 807166A1 | |
| MerCruiser | 4.3L MPI ALPHA/BRAVO | 4-Stroke | 1998 and newer | 807166A1 | |
| MerCruiser | 5.7L (2 BBL.) GM 350 V-8 | 4-Stroke | 1998–2001 | 807166A1 | |
| MerCruiser | 350 MAG MPI HORIZON ALPHA/BRAVO EC | 4-Stroke | 1998 and newer | 807166A1 | |
| MerCruiser | 4.3L EFI (GEN+) TBI GM 262 V-6 | 4-Stroke | 1998 and newer | 807166A1 | |
| MerCruiser | 350 MAG MPI HORIZON ALPHA/BRAVO | 4-Stroke | 1998 and newer | 807166A1 | |
| MerCruiser | 4.3L (GEN II) (2 BBL.) GM 262 V-6 | 4-Stroke | 1992–1993 | 807166A1 | |
| MerCruiser | MX 6.2L MPI HORIZON BRAVO | 4-Stroke | 1998 and newer | 807166A1 | |
| MerCruiser | 4.5L MPI 250 Alpha/Bravo EC | 4-Stroke | 1998 and newer | 807166A1 | |
| MerCruiser | 383 MAG STROKER | 4-Stroke | 1998 and newer | 807166A1 | |
| MerCruiser | 5.0L (2 BBL.) GM 305 V-8 | 4-Stroke | 1998–2001 | 807166A1 | |
| MerCruiser | V6 engines with standard manifolds | 4-Stroke | 1998 and newer | 807166A1 | Not for batwing V6 manifolds |
| MerCruiser | V8 engines | 4-Stroke | 1998 and newer | 807166A1 | Compatible with 4-inch oval Y-pipes |
Technical Specs
- Product Type
- Water Shutter Kit
- Installation
- Y-pipe mount
- Connection
- Rectangular pin holes
- Housing Material
- Rubber with metal rod
- Housing Color
- Black
- Dimensions
- Fits oval 4-inch Y-pipes
- Fitting Type
- 2-piece clapper design
- Other Technical Attributes
- Acts as a check valve to prevent following seas/water from washing back through exhaust to engine when not running or at low RPM
What’s in the Box
- 1 x Water Shutter Kit (807166A1)
Installation Notes
Installation typically requires access to the exhaust Y-pipe, which may involve removing the stern drive unit. After gaining access, remove the exhaust bellows to reach the old water shutter. Pry out the old shutter and replace it with the new unit, ensuring the metal rod and clapper assembly are correctly oriented and securely seated in the Y-pipe's pin holes. Reassemble all components and test the engine operation, checking for any exhaust leaks.
Troubleshooting & FAQ
How do I know if this water shutter fits my engine?
This kit is for MerCruiser V6 and V8 engines made in 1998 or later that have an oval 4-inch exhaust Y-pipe with rectangular pin holes. It will not fit V6 engines with one-piece "batwing" style manifolds, which require part 807166A2. For engines made before 1996, you may need part 807166A3, which includes an adapter carrier.
What is the main function of a water shutter?
A water shutter, or exhaust flapper, acts as a one-way valve in your exhaust system. It opens to let exhaust gases out but closes to prevent a following sea or wave from forcing water back up the exhaust pipe and into the engine, which could cause catastrophic damage.
What are common signs of a failing water shutter?
The most common symptom is a distinct rattling or clunking sound from the exhaust area at idle, which disappears at higher RPMs. You might also find broken pieces of black rubber in the exhaust outlet or notice reduced engine performance. In severe cases, failure can lead to water ingestion in the cylinders.
ins>How often should I inspect or replace my water shutters?
Water shutters are considered a maintenance item. They are made of rubber and degrade over time from heat and exhaust chemicals. It is best practice to inspect them annually (e.g., during winterization) and replace them if they show any signs of cracking, brittleness, missing pieces, or damage.
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.
Payment & Security
Payment methods
Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.
