Water Pump Impeller Kit for Yamaha T25 HP 38837, F30 HP 38837, F40 HP 00-05 66T-W0078-00
Water Pump Impeller Kit for Yamaha T25 HP 38837, F30 HP 38837, F40 HP 00-05 66T-W0078-00 is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
Delivery and Shipping
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Water Pump Impeller Kit for Yamaha T25 HP 38837, F30 HP 38837, F40 ...
Water Pump Impeller Kit for Yamaha T25 HP 38837, F30 HP 38837, F40 HP 00-05 66T-W0078-00 is backordered and will ship as soon as it is back in stock.
Product Details
This Water Pump Impeller Kit – Fits Yamaha F30, F40, T25 4-Stroke Outboard (Replaces 66T-W0078-00) provides all necessary components to service your outboard's cooling system. It is designed for a precise fit on Yamaha 4-Stroke 25–40 HP models (T25, F30, F40) from approximately 2000–2008, with extended compatibility for some newer models.
This kit serves as a direct interchange for Yamaha 66T-W0078-00, 66T-W0078-01, 66T-W0078-A0; Sierra 18-3413, 18-3440; and Mallory MAL9-48610.
- Installs as a direct replacement for original factory pump components.
- Constructed with a marine-grade metal pump housing and a durable neoprene rubber impeller for longevity.
- The 6-blade impeller comes with the necessary woodruff key for a secure fit on the 16mm shaft.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Yamaha | 66T-W0078-00 |
| Yamaha | 66T-W0078-01 |
| Yamaha | 66T-W0078-A0 |
| Sierra | 18-3413 |
| Sierra | 18-3440 |
| Mallory | MAL9-48610 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
Compatibility includes a range of Yamaha 2-stroke and 4-stroke models. Please verify your specific engine model and year below.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Yamaha | T25 | 25 | 4-Stroke | 2001–2004 | 66T-W0078-00 | |
| Yamaha | T25 | 25 | 4-Stroke | 2005–2008 | 66T-W0078-00 | |
| Yamaha | T25LA | 25 | 4-Stroke | 2009–2019 | 66T-W0078-00 | Extended compatibility per Soxa Marine |
| Yamaha | T25TLRZ | 25 | 4-Stroke | 2001 | 66T-W0078-00 | |
| Yamaha | T25TLRA | 25 | 4-Stroke | 2002 | 66T-W0078-00 | |
| Yamaha | T25TLRB | 25 | 4-Stroke | 2003 | 66T-W0078-00 | |
| Yamaha | T25TLRC | 25 | 4-Stroke | 2004 | 66T-W0078-00 | |
| Yamaha | T25TLR, T25TLRD | 25 | 4-Stroke | 2005 | 66T-W0078-00 | |
| Yamaha | T25TLR | 25 | 4-Stroke | 2006 | 66T-W0078-00 | |
| Yamaha | F30 | 30 | 4-Stroke | 2001–2004 | 66T-W0078-00 | |
| Yamaha | F30TLR, F30TLRD | 30 | 4-Stroke | 2005 | 66T-W0078-00 | |
| Yamaha | F30TLRZ | 30 | 4-Stroke | 2001 | 66T-W0078-00 | |
| Yamaha | F30TLRA | 30 | 4-Stroke | 2002 | 66T-W0078-00 | |
| Yamaha | F30TLRB | 30 | 4-Stroke | 2003 | 66T-W0078-00 | |
| Yamaha | F30TLRC | 30 | 4-Stroke | 2004 | 66T-W0078-00 | |
| Yamaha | F40 | 40 | 4-Stroke | 2000–2004 | 66T-W0078-00 | |
| Yamaha | F40 | 40 | 4-Stroke | 2005–2008 | 66T-W0078-00 | |
| Yamaha | F40TLRY, F40MLHY, F40MSHY, F40ESRY | 40 | 4-Stroke | 2000 | 66T-W0078-00 | |
| Yamaha | F40ESRZ, F40MSHZ, F40TLRZ, F40MLHZ | 40 | 4-Stroke | 2001 | 66T-W0078-00 | |
| Yamaha | F40ESRA, F40MJHA, F40TLRA, F40MSHA, F40MLHA | 40 | 4-Stroke | 2002 | 66T-W0078-00 | |
| Yamaha | F40MSHB, F40TLRB, F40MLHB, F40ESRB, F40MJHB, F40EJRB | 40 | 4-Stroke | 2003 | 66T-W0078-00 | |
| Yamaha | F40MSHC, F40MJHC, F40EJRC, F40MLHC, F40TLRC | 40 | 4-Stroke | 2004 | 66T-W0078-00 | |
| Yamaha | F40EJR, F40MSH, F40TLR, F40MJH, F40MLH variants | 40 | 4-Stroke | 2005 | 66T-W0078-00 | Multiple variants with different suffixes |
| Yamaha | F40EJR, F40MJH, F40MLH, F40MSH, F40TLR | 40 | 4-Stroke | 2006 | 66T-W0078-00 | |
| Yamaha | F40BMJH, F40BTLR, F40BMLH, F40BEJR | 40 | 4-Stroke | 2007 | 66T-W0078-00 | |
| Yamaha | F40BTLR, F40BMLH | 40 | 4-Stroke | 2008 | 66T-W0078-00 | |
| Yamaha | 40X, 40XWT, E40X | 40 | 2-Stroke | 1998+ | 66T-W0078-00 | Per JLM Marine |
Technical Specs
- Product Type
- Water Pump Impeller Kit / Water Pump Service Kit
- Installation
- Direct replacement for OEM pump components
- Housing Material
- Marine-grade metal (pump housing) with neoprene rubber impeller
- Dimensions
- 52mm impeller diameter × 19mm width (impeller only)
- Technical Attributes
- 6-blade impeller design with 16mm shaft size, includes woodruff key
What’s in the Box
- 1 x Pump Housing (66T-44311-00-00)
- 1 x Water Pump Impeller (6H4-44352-00-00/6H4-44352-02-00)
- 1 x Cartridge Insert (63D-44322-00-00)
- 1 x Outer Plate (66T-44323-00-00)
- 1 x Gasket (63D-44316-00-00)
- 1 x Cover/Pump Housing Cover (63D-44312-00-00
- 1 x Woodruff Key (90280-03M03-00)
- 1 x O-ring (93210-59MG7-00)
- 1 x Seal/Water Seal Damper (663-44366-00-00)
- 4 x Bolts/Washer (90119-08M15-00)
Installation Notes
- Disconnect the engine's battery before beginning work.
- Remove the lower unit (gearcase) from the outboard motor.
- Unbolt and carefully remove the old water pump housing.
- Inspect and note the orientation of the old components before removal.
- Thoroughly clean the mounting surfaces and remove any old gasket material.
- Install the new gaskets, wear plate, and cartridge insert from the kit.
- Slide the new impeller onto the driveshaft. Ensure the woodruff key is properly seated and rotate the shaft clockwise to bed the impeller vanes.
- Align and install the new pump housing, securing it with the provided bolts.
- Reinstall the lower unit onto the outboard motor.
- Reconnect the battery and test the engine in a suitable water supply to confirm proper water flow from the tell-tale outlet.
Troubleshooting & FAQ
How do I know if this kit fits my Yamaha outboard?
This kit is primarily for Yamaha T25, F30, and F40 4-stroke models from 2000–2008. Always verify your specific engine model and year against the compatibility table provided. For models outside this range, check the table for extended compatibility notes confirmed by secondary sources.
What are the signs of a failing water pump impeller?
Common symptoms include the engine overheating, a weak or non-existent water stream from the "tell-tale" exhaust outlet, or a temperature alarm from your engine's warning system.
How often should the water pump impeller be replaced?
As a general maintenance guideline, it's recommended to inspect the impeller annually and replace it every 1–2 years or every 100–200 hours of operation, whichever comes first. Service intervals should be shorter in saltwater or silty conditions.
Do I need to use all the parts in the kit?
Yes, this is a complete service kit. It is highly recommended to replace all included components—such as the housing, gaskets, seals, and plates—at the same time to ensure a reliable, leak-free repair and restore original performance.
What's the difference between OEM 66T-W0078-01 and 66T-W0078-A0?
The -01 and -A0 suffixes typically denote minor revisions or supersessions by the original manufacturer. This aftermarket kit is engineered to be a direct replacement for all listed variations, including 66T-W0078-00, ensuring the same fit and function.
OEM vs. Aftermarket?
This listing is an aftermarket replacement (not OEM). It is built to OEM-level specifications with comparable materials and manufactured in an ISO 9002 facility, with batch-inspected for consistency and quality control.
Shipping speed & cost?
We ship worldwide quickly—typical transit is 5–15 days. Standard shipping is free to most regions; expedited options will appear at checkout where available.
Warranty & returns?
Our products are covered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact our support team with your order details. Returns are accepted within our standard window for unused items in their original condition. See our policy page or reach out for instructions.
Safety & Important Info
- Verify images and specifications against your original part. If anything differs—even if your model appears compatible—do not purchase.
- This is an aftermarket replacement part, not an OEM component. Brand names and part numbers are used for reference purposes only.
- Professional installation is recommended for safety and optimal performance. Improper installation can lead to engine damage.
About Sea Sierra
- Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and rigoriously tested for real-world conditions.
- Fast Global Fulfillment — We offer free standard delivery to most regions, with typical transit times of 5–15 days.
- Manufacturer-Direct Value — By working directly with manufacturers, we provide fair pricing without compromising on materials or quality control.
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