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

🚤 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 of Failure

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

🔄 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

📦 Condition

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