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Serdamarine  |  SKU: 17ST005

807166A3 2.50 in. Exhaust Water Shutter Set (2 Pcs) for Mercruiser

Regular price $31.00


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SERDAMARINE / MARINE EXHAUST PARTS

Exhaust Water Shutter Set — 2 Pieces (2.50 in. Cross Pin Diameter)

This two-piece exhaust water shutter flapper valve set is designed for Mercruiser Stern / Out Drive exhaust systems and references 807166A3. Each shutter features a 2.50-inch diameter at the cross pin and acts as a flexible check valve to stop water from returning up the exhaust system toward the engine.

Configuration & Specifications

Diameter at Cross Pin 2.50 in. (measured at the cross pin; do not treat this measurement as the exhaust pipe diameter)
Valve Function Flexible check valve (flapper valve) to stop water from returning up the exhaust system to the engine

Engine Applications

For Mercruiser Stern / Out Drive exhaust systems requiring a 2.50-inch diameter at the water shutter cross pin. Verify the original exhaust-system version, the original shutter part number, and the 2.50-inch cross-pin measurement before ordering.

  • Mercruiser Stern / Out Drive — Exhaust systems using water shutters with a 2.50 in. diameter at the cross pin. Fits when specified: Requires matching exhaust-system version and 2.50 in. cross-pin diameter.

Reference Numbers

The numbers below are provided for part identification and reference only; they do not alone guarantee interchangeability across different exhaust configurations or indicate manufacturer identity.

Two-Piece Set Reference 807166A3*2
Mercury Mariner References 807166A3, 807166A 3, 14348, 143481, 14348A1, 14348A2
Sierra / Sierra Marine 18-2732, 18-2732-9, 18-2733
Mallory / Mallory Marine 9-42802, 89170
GLM 89170
RECMAR REC807166A3

Supplied Parts

  • Exhaust water shutter — 2 pieces

This set contains two exhaust water shutters only, not a complete exhaust manifold.

Service & Installation Notes

General service guidance only. Use the service manual for your exact engine and exhaust configuration.

  1. Ensure the engine is shut off, completely cool, and secured against accidental starting before working on the exhaust system.
  2. Remove the existing water shutters and inspect the exhaust passage for loose fragments or wear from the previous shutters.
  3. Compare the replacement shutters against the original parts, verifying the 2.50-inch diameter at the cross pin and the exhaust-system version.
  4. Seat the cross pin properly into the exhaust passage according to your engine service manual and verify that the flapper halves move freely without binding.
  5. After reassembly, monitor the exhaust system during initial operation; shut down the engine and inspect immediately if abnormal noise or exhaust restriction occurs.

The Serdamarine Approach

Exhaust parts need a configuration match. Serdamarine focuses on marine exhaust manifolds and their related service parts. Application details, connection requirements and public reference numbers are presented together to support part selection.

Questions Before Replacement

Does the 2.50-inch measurement refer to the exhaust pipe diameter?

No. The 2.50-inch measurement specifies the diameter of the water shutter at the cross pin, not the inside or outside diameter of the exhaust pipe.

What is included in this listing?

This listing supplies a set of 2 exhaust water shutters (flapper valves). It does not include an exhaust manifold or exhaust pipes.

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