# 663-44315-A0 Yamaha gasket | Genuine OEM Yamaha Outboard Part

🔧 Product Description

  

Genuine Yamaha Water Pump Wear Plate Gasket - Part Number: 663-44315-A0

  

A genuine Yamaha lower water-pump gasket fitted beneath the wear plate on selected 40HP and 50HP two-stroke outboards.

  

The gasket seals the lower face of the stainless pump plate against the gearcase or pump base, preventing cooling-water pressure from escaping beneath the impeller assembly.

  

⚙️ Key Features

  

• Genuine Yamaha OEM water-pump gasket

• Correct Yamaha part number 663-44315-A0

• Lower wear-plate sealing position

• Used in selected Yamaha 40HP and 50HP two-stroke pumps

• Cross-references with Sierra and Recmar replacements

  

🔄 Supersession & Cross Reference

  

OEM Supersession Chain:

  

• 663-44315-A0 current Yamaha OEM water-pump gasket reference

  

OEM / Related Numbers:

  

• 663-44315-A0

• 663-44315-A0-00

• 66344315A000

• 663-44316-A0 related upper wear-plate gasket

• 663-44322-00 related pump insert

• 663-44323-00 related water-pump outer plate

• 663-44324-A0 related cartridge gasket

• 663-W0078-00 related water-pump repair kit

  

Aftermarket / Verified Equivalents:

  

• Sierra: 18-0292

• Recmar: REC663-44315-A0

• Included in Sierra lower-unit seal kit 18-2789

• Included in Sierra water-pump kit 18-3430

  

🚤 Compatibility

  

Commonly used on:

  

• Yamaha 40HP and 50HP two-stroke lower-unit water pumps

• Pump assemblies using the 663-series wear plate and cartridge components

  

Typically suits:

  

• Engine models:

• Yamaha 40HP two-stroke - approximately 1984-1994

• Yamaha 40E, 40H, 40J, 40N, 40Q and related 663-series gearcases

• Yamaha 50HP two-stroke - approximately 1984-1987

• Yamaha 50HP Pro Series - approximately 1987-1990

• Yamaha P50 - approximately 1995-1996

• Yamaha 50D, 50G and 50H lower units using the 663-series water pump

  

• HP Range: 40HP - 50HP

• Engine Type: Yamaha carburetted two-stroke outboard

• Year Range: Approximately 1984 - 1996, dependent on gearcase

  

🔌 Function

  

The gasket seals beneath the water-pump wear plate so cooling water is drawn through the inlet and directed into the pump without bypassing the impeller chamber.

  

Common signs of failure:

  

• Weak cooling-water flow after water-pump service

• Engine overheating despite a serviceable impeller

• Water leaks beneath the wear plate

• Gasket tears during pump disassembly

• Corrosion or old gasket material prevents the plate from sitting flat

  

📦 Condition

  

• Genuine Yamaha part

• Brand new

• Supplied in original or equivalent packaging

## Details

- **Price:** 7.0 AUD
- **Vendor:** Yamaha
- **Tags:** Yamaha Marine Parts | Outboard Engine Parts & Components

## Variants

| Variant | Price | Available |
|---------|-------|-----------|
| Default Title | 7.00 AUD | In stock |

## Images

- 663-44315-A0 Yamaha gasket | Genuine OEM Yamaha Outboard Part

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> Source: [Sawley's Auto and Marine](https://www.sawleysautoandmarine.com.au/products/663-44315-a0-gasket)
> Updated: 2026-07-11