Water Pump Repair Kit – Fits Yamaha T25, F30, F40 Outboards (Replaces 66T-W0078-00, 66T-W0078-01)
Water Pump Repair Kit – Fits Yamaha T25, F30, F40 Outboards (Replaces 66T-W0078-00, 66T-W0078-01) is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
Delivery and Shipping
Orders are typically processed within 1–2 business days.
U.S. orders usually arrive within 6–15 days, depending on stock location and destination.
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Water Pump Repair Kit – Fits Yamaha T25, F30, F40 Outboards (Replac...
Water Pump Repair Kit – Fits Yamaha T25, F30, F40 Outboards (Replaces 66T-W0078-00, 66T-W0078-01) is backordered and will ship as soon as it is back in stock.
Product Details
This Water Pump Repair Kit – Fits Yamaha T25, F30, F40 Outboards (Replaces 66T-W0078-00, 66T-W0078-01) is a comprehensive solution engineered for Yamaha 4-stroke outboard engines. It is specifically designed for T25, F30, and F40 models manufactured between 2000 and 2009, providing all necessary components to restore cooling system performance.
This kit serves as a direct replacement for Yamaha part numbers 66T-W0078-00-00 and 66T-W0078-01-00, and also cross-references with Sierra 18-3413, 18-3440, and Mallory Marine MAL9-48610.
- Engineered for direct OEM replacement and fitment.
- Includes a new impeller, housing, gaskets, and hardware.
- Designed specifically for 4-stroke outboard engines.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Yamaha | 66T-W0078-00-00 |
| Yamaha | 66T-W0078-01-00 |
| Sierra | 18-3413 |
| Sierra | 18-3440 |
| Mallory Marine | MAL9-48610 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
This kit is verified for the following Yamaha outboard models.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Yamaha | T25 | 25 | 4-Stroke | 2001–2019 | 66T-W0078-00-00 | |
| Yamaha | T25LA | 25 | 4-Stroke | 2009–2019 | 66T-W0078-00-00 | |
| Yamaha | T25TLR | 25 | 4-Stroke | 2001–2006 | 66T-W0078-00-00 | |
| Yamaha | T25TLRA | 25 | 4-Stroke | 2002 | 66T-W0078-00-00 | |
| Yamaha | T25TLRB | 25 | 4-Stroke | 2003 | 66T-W0078-00-00 | |
| Yamaha | T25TLRC | 25 | 4-Stroke | 2004 | 66T-W0078-00-00 | |
| Yamaha | T25TLRD | 25 | 4-Stroke | 2005 | 66T-W0078-00-00 | |
| Yamaha | T25TLRZ | 25 | 4-Stroke | 2001 | 66T-W0078-00-00 | |
| Yamaha | F30 | 30 | 4-Stroke | 2001–2005 | 66T-W0078-00-00 | |
| Yamaha | F30TLR | 30 | 4-Stroke | 2001–2005 | 66T-W0078-00-00 | |
| Yamaha | F30TLRA | 30 | 4-Stroke | 2002 | 66T-W0078-00-00 | |
| Yamaha | F30TLRB | 30 | 4-Stroke | 2003 | 66T-W0078-00-00 | |
| Yamaha | F30TLRC | 30 | 4-Stroke | 2004 | 66T-W0078-00-00 | |
| Yamaha | F30TLRD | 30 | 4-Stroke | 2005 | 66T-W0078-00-00 | |
| Yamaha | F30TLRZ | 30 | 4-Stroke | 2001 | 66T-W0078-00-00 | |
| Yamaha | F40 | 40 | 4-Stroke | 2000–2008 | 66T-W0078-00-00 | |
| Yamaha | F40BEJR | 40 | 4-Stroke | 2004–2007 | 66T-W0078-00-00 | |
| Yamaha | F40BMJH | 40 | 4-Stroke | 2004–2007 | 66T-W0078-00-00 | |
| Yamaha | F40BMLH | 40 | 4-Stroke | 2004–2008 | 66T-W0078-00-00 | |
| Yamaha | F40BTLR | 40 | 4-Stroke | 2004–2008 | 66T-W0078-00-00 | |
| Yamaha | F40EJR | 40 | 4-Stroke | 2003–2006 | 66T-W0078-00-00 | |
| Yamaha | F40EJRB | 40 | 4-Stroke | 2003 | 66T-W0078-00-00 | |
| Yamaha | F40EJRC | 40 | 4-Stroke | 2004 | 66T-W0078-00-00 | |
| Yamaha | F40EJRD | 40 | 4-Stroke | 2005 | 66T-W0078-00-00 | |
| Yamaha | F40ESRA | 40 | 4-Stroke | 2002 | 66T-W0078-00-00 | |
| Yamaha | F40ESRB | 40 | 4-Stroke | 2003 | 66T-W0078-00-00 | |
| Yamaha | F40ESRY | 40 | 4-Stroke | 2000 | 66T-W0078-00-00 | |
| Yamaha | F40ESRZ | 40 | 4-Stroke | 2001 | 66T-W0078-00-00 | |
| Yamaha | F40MJH | 40 | 4-Stroke | 2002–2006 | 66T-W0078-00-00 | |
| Yamaha | F40MJHA | 40 | 4-Stroke | 2002 | 66T-W0078-00-00 | |
| Yamaha | F40MJHB | 40 | 4-Stroke | 2003 | 66T-W0078-00-00 | |
| Yamaha | F40MJHC | 40 | 4-Stroke | 2004 | 66T-W0078-00-00 | |
| Yamaha | F40MJHD | 40 | 4-Stroke | 2005 | 66T-W0078-00-00 | |
| Yamaha | F40MLH | 40 | 4-Stroke | 2002–2006 | 66T-W0078-00-00 | |
| Yamaha | F40MLHA | 40 | 4-Stroke | 2002 | 66T-W0078-00-00 | |
| Yamaha | F40MLHB | 40 | 4-Stroke | 2003 | 66T-W0078-00-00 | |
| Yamaha | F40MLHC | 40 | 4-Stroke | 2004 | 66T-W0078-00-00 | |
| Yamaha | F40MLHD | 40 | 4-Stroke | 2005 | 66T-W0078-00-00 | |
| Yamaha | F40MLHY | 40 | 4-Stroke | 2000 | 66T-W0078-00-00 | |
| Yamaha | F40MLHZ | 40 | 4-Stroke | 2001 | 66T-W0078-00-00 | |
| Yamaha | F40MSH | 40 | 4-Stroke | 2002–2006 | 66T-W0078-00-00 | |
| Yamaha | F40MSHA | 40 | 4-Stroke | 2002 | 66T-W0078-00-00 | |
| Yamaha | F40MSHB | 40 | 4-Stroke | 2003 | 66T-W0078-00-00 | |
| Yamaha | F40MSHC | 40 | 4-Stroke | 2004 | 66T-W0078-00-00 | |
| Yamaha | F40MSHD | 40 | 4-Stroke | 2005 | 66T-W0078-00-00 | |
| Yamaha | F40MSHY | 40 | 4-Stroke | 2000 | 66T-W0078-00-00 | |
| Yamaha | F40MSHZ | 40 | 4-Stroke | 2001 | 66T-W0078-00-00 | |
| Yamaha | F40TLR | 40 | 4-Stroke | 2002–2006 | 66T-W0078-00-00 | |
| Yamaha | F40TLRA | 40 | 4-Stroke | 2002 | 66T-W0078-00-00 | |
| Yamaha | F40TLRB | 40 | 4-Stroke | 2003 | 66T-W0078-00-00 | |
| Yamaha | F40TLRC | 40 | 4-Stroke | 2004 | 66T-W0078-00-00 | |
| Yamaha | F40TLRD | 40 | 4-Stroke | 2005 | 66T-W0078-00-00 | |
| Yamaha | F40TLRY | 40 | 4-Stroke | 2000 | 66T-W0078-00-00 | |
| Yamaha | F40TLRZ | 40 | 4-Stroke | 2001 | 66T-W0078-00-00 | |
| Yamaha | 40XMH | 40 | 4-Stroke | 66T-W0078-00-00 | ||
| Yamaha | 40XE | 40 | 4-Stroke | 66T-W0078-00-00 |
Technical Specs
- Product Type
- Outboard Water Pump Repair Kit
- Installation
- Direct OEM replacement
- Engine Type
- For 4-stroke outboard engines
What’s in the Box
- 1 x Pump Housing Cover (63D-44312-00-00)
- 1 x Cartridge Insert (63D-44322-00-00)
- 1 x Cartridge Outer Plate (66T-44323-00-00)
- 1 x O-Ring (93210-59MG7-00)
- 1 x Water Pump Gasket (63D-44316-00-00)
- 1 x Woodruff Key (90280-03M03-00)
- 1 x Impeller (6H4-44352-02-00)
- 4 x Bolt, With Washer (90119-08M15-00)
- 1 x Water Seal Damper (663-44366-00-00)
Installation Notes
- Disconnect the battery and ensure the engine is off and cool.
- Remove the lower unit (gearcase) from the outboard motor. Refer to your service manual for specific instructions.
- Unbolt and carefully remove the old water pump housing.
- Remove the old impeller, gaskets, plates, and O-rings. Note their orientation.
- Thoroughly clean all mating surfaces, removing any old gasket material or corrosion.
- Install the new components from the kit in the reverse order of disassembly.
- Lightly grease the new impeller and housing interior. Ensure the Woodruff key is correctly seated in the driveshaft.
- Slide the new impeller onto the driveshaft while turning the shaft clockwise to bed the vanes correctly.
- Bolt the new pump housing down to the manufacturer's specified torque.
- Reinstall the lower unit, making sure the water tube aligns with the pump outlet.
- Reconnect the battery. Before launching, use a flusher to test the engine on land, confirming a steady water stream from the tell-tale outlet.
Troubleshooting & FAQ
How do I know if my water pump is failing?
Common signs include a weak, intermittent, or completely absent water stream from the engine's tell-tale outlet. You may also receive an engine overheating alarm or notice the engine running hotter than usual. A deformed, cracked, or stiff impeller found during inspection is a clear sign that replacement is needed.
How often should I replace my water pump kit?
For preventative maintenance, it is recommended to inspect and/or replace the impeller and associated seals every 1 to 2 years, or every 100-200 hours of operation. Frequency should be increased if operating primarily in saltwater, silty, or sandy conditions.
What is the difference between Yamaha parts 66T-W0078-00 and 66T-W0078-01?
The part number 66T-W0078-01-00 is a supersession or revision of the original 66T-W0078-00-00 kit. They are functionally identical, and this aftermarket kit is a direct replacement for both versions, fitting all specified applications without modification.
Can I install just the impeller instead of the whole kit?
While possible, it is not recommended. The housing, wear plates, and seals degrade over time and can cause premature failure of a new impeller. Installing the complete kit ensures all wear components are new, providing greater reliability and restoring original performance.
Is this kit for 2-stroke or 4-stroke engines?
This kit is designed exclusively for the 4-stroke Yamaha outboard models listed in the compatibility table, including the T25, F30, and F40 series.
OEM vs. Aftermarket?
This listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.
Shipping speed & cost?
We ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.
Warranty & returns?
Covered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused & in original condition). See our policy page or reach out for instructions.
Safety & Important Info
- Verify images/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.
- This is an aftermarket replacement, not an OEM component.
- Professional installation is recommended for safety and performance.
About Sea Sierra
- Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.
- Fast Global Fulfillment — Free standard delivery to most regions in 5–15 days.
- Manufacturer-Direct Value — Fair pricing without compromising on materials or QC.
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