90280-04M05 Yamaha Woodruff Key | Genuine OEM Yamaha Outboard Part

🔧 Product Description

Genuine Yamaha High-Horsepower Water Pump Woodruff Key - Part Number: 90280-04M05

A genuine Yamaha woodruff key used to drive the water-pump impeller on selected V4 and high-horsepower outboard lower units.

The key fits into the driveshaft keyway and engages the impeller hub, ensuring the impeller rotates at driveshaft speed.

⚙️ Key Features

• Genuine Yamaha OEM water-pump drive key
• Correct Yamaha part number 90280-04M05
• Precision-machined semicircular profile
• Included in Yamaha 6N6-series water-pump kits
• Sierra replacement key available

🚤 Compatibility

Commonly used on

• Yamaha V4 and high-horsepower lower-unit water pumps
• Impeller installations using the 6E5-series pump components

Typically suits

• Engine models:
• Yamaha 100A two-stroke
• Yamaha 115B and 115C two-stroke
• Yamaha 130B two-stroke
• Yamaha 140B two-stroke
• Yamaha 115HP V4 production from approximately 1984 onward where specified
• Yamaha F115A early four-stroke
• Water-pump kit 6N6-W0078-02
• High-horsepower lower units using impeller 6E5-44352-01
• HP Range: Approximately 100HP - 140HP, with additional 6E5 pump-family applications
• Engine Type: Yamaha V4 two-stroke and early F115 four-stroke outboard
• Year Range: Lower-unit and pump-design controlled.

🔌 Function

The key mechanically couples the impeller to the driveshaft so the pump turns whenever the engine driveshaft rotates.

⚠️ Common Signs of Failure

• Impeller does not rotate
• Engine overheats immediately after pump service
• Key is missing during assembly
• Key is sheared or rolled over
• Impeller hub or driveshaft keyway is damaged

🔄 Supersession & Cross Reference

OEM Supersession Chain

• 90280-04M05 current OEM water-pump woodruff-key reference

OEM / Related Numbers

• 90280-04M05
• 90280-04M05-00
• 6N6-W0078-02 related pump kit
• 6E5-44352-01 related impeller

Aftermarket / Verified Equivalents

• Sierra: 18-3302
• Aftermarket Yamaha impeller drive key: 90280-04M05

📦 Condition

• Genuine Yamaha part
• Brand new
• Supplied in original or equivalent packaging