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