# 66T-W0078-01 Yamaha Water Pump Repair Kit | Genuine OEM Yamaha Outboard Part

🔧 Product Description

  

Genuine Yamaha Water Pump Repair Kit - Part Number: 66T-W0078-01

  

A genuine Yamaha lower-unit water-pump service kit for selected 25HP, 30HP and 40HP four-stroke outboards.

  

The kit contains the principal components required to renew the impeller and associated pump sealing parts. It is intended for routine cooling-system maintenance or repair after overheating, impeller damage or reduced water flow.

  

⚙️ Key Features

  

• Genuine Yamaha OEM water-pump repair kit

• Correct Yamaha part number 66T-W0078-01

• Replaces earlier 66T-W0078-00 kit

• Services selected 25HP to 40HP four-stroke lower units

• Cross-references with Sierra, Mallory and Recmar pump kits

  

🔄 Supersession & Cross Reference

  

OEM Supersession Chain:

  

• 66T-W0078-01 → Supersedes 66T-W0078-00

• 66T-W0078-00 earlier Yamaha water-pump kit reference

• 66T-W0078-A0 alternate Yamaha kit reference

  

OEM / Related Numbers:

  

• 66T-W0078-01

• 66T-W0078-01-00

• 66TW00780100

• 66T-W0078-00

• 66T-W0078-A0

• 66T-44311-00 related pump housing

• 66T-44352-00 related impeller

• 66T-44322-00 related pump insert

  

Aftermarket / Verified Equivalents:

  

• Sierra: 18-3440

• Sierra complete kit with housing: 18-3413

• Mallory: 9-48610

• Recmar: REC66T-W0078-00

• SeaSierra: 18-3413 / 18-3440

  

🚤 Compatibility

  

Commonly used on:

  

• Yamaha 25HP, 30HP and 40HP four-stroke lower-unit water pumps

  

Typically suits:

  

• Engine models:

• Yamaha F25 four-stroke 2-cylinder - approximately 2001-2019

• Yamaha T25 four-stroke - approximately 2001-2005

• Yamaha F30 four-stroke 3-cylinder - approximately 2001-2019

• Yamaha F30A four-stroke

• Yamaha F40 four-stroke 3-cylinder - approximately 2000-2019

• Yamaha F40A and F40B applications using the 66T-series gearcase

  

• HP Range: 25HP - 40HP

• Engine Type: Yamaha four-stroke outboard

• Year Range: Approximately 2000 - 2019, dependent on gearcase

  

🔌 Function

  

The kit renews the water-pump components responsible for drawing cooling water through the lower unit and circulating it through the engine.

  

Common signs the kit is required:

  

• Weak or intermittent tell-tale stream

• Engine overheats at idle or under load

• Impeller blades are cracked, stiff or missing

• Pump housing contains rubber debris or scoring

• Water-pump service interval has been reached

  

📦 Condition

  

• Genuine Yamaha part

• Brand new

• Supplied in original or equivalent packaging

## Details

- **Price:** 100.0 AUD
- **Vendor:** Yamaha
- **Tags:** Yamaha Marine Parts | Outboard Engine Parts & Components

## Variants

| Variant | Price | Available |
|---------|-------|-----------|
| Default Title | 100.00 AUD | In stock |

## Images

- 66T-W0078-01 Yamaha Water Pump Repair Kit | Genuine OEM Yamaha Outboard Part

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> Source: [Sawley's Auto and Marine](https://www.sawleysautoandmarine.com.au/products/66t-w0078-01-00-water-pump-repair-kit)
> Updated: 2026-07-11