# 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

  

🔄 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

  

🚤 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

  

📦 Condition

  

• Genuine Yamaha part

• Brand new

• Supplied in original or equivalent packaging

## Details

- **Price:** 20.22 AUD
- **Vendor:** Yamaha
- **Tags:** Yamaha Marine Parts | Outboard Engine Parts & Components

## Variants

| Variant | Price | Available |
|---------|-------|-----------|
| Default Title | 20.22 AUD | In stock |

## Images

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

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> Source: [Sawley's Auto and Marine](https://www.sawleysautoandmarine.com.au/products/90280-04m05-woodruff-key)
> Updated: 2026-07-11