Water Pump Repair Kit for Yamaha 50–70 HP Outboards – Replaces 6H3-W0078-02-00
Water Pump Repair Kit for Yamaha 50–70 HP Outboards – Replaces 6H3-W0078-02-00 is backordered and will ship as soon as it is back in stock.
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Water Pump Repair Kit for Yamaha 50–70 HP Outboards – Replaces 6H3-...
Water Pump Repair Kit for Yamaha 50–70 HP Outboards – Replaces 6H3-W0078-02-00 is backordered and will ship as soon as it is back in stock.
Product Details
This aftermarket water pump repair kit is designed to service the cooling-system water pump on selected Yamaha 50–70 HP outboard applications. It replaces the Yamaha water pump repair kit reference 6H3-W0078-02-00 and is intended for direct replacement of the listed service components when the exact engine model and year match the compatibility information below.
Catalog applications for this water pump repair kit include selected Yamaha 2-Stroke 50–70 HP models from the late 1990s through the 2000s, together with selected 4-Stroke F50 applications. Yamaha model codes, production years, shaft configuration, and serial-number conditions can affect fitment, so confirm your complete engine identification before ordering.
- Replacement water-pump service kit for the listed Yamaha outboard applications.
- Includes a neoprene-rubber impeller and the gaskets, wear parts, cup, key, fasteners, and O-ring listed in the package contents.
- Designed to restore water-pump sealing and cooling-water flow during routine service.
- Aftermarket replacement; not manufactured or branded by Yamaha.
Part Number Matrix
These references are provided for identification and cross-reference purposes. Confirm the original pump assembly and application before installation.
| Brand or Source | Part Number | Reference |
|---|---|---|
| Yamaha | 6H3-W0078-02-00 | Primary OEM reference for the water pump repair kit |
| Yamaha | 6H3-W0078-01-00 | Earlier related reference |
| Yamaha | 6H3-W0078-A0-00 | Earlier related reference; verify application and production year |
| Sierra | 18-3465 | Aftermarket reference commonly listed without a housing |
| Sierra | 18-3466 | Different aftermarket configuration commonly listed with a housing; not the package described here |
Engine & Model Compatibility
The catalog records reviewed identify this repair-kit reference on multiple Yamaha applications. The examples below are organized by stroke type. Do not use horsepower alone to determine fitment; compare the complete model code, year, shaft configuration, and serial range with your engine.
Selected Yamaha 2-Stroke Applications
| Model Examples | Rated HP | Stroke | Catalog Years Represented | OEM Reference |
|---|---|---|---|---|
| 60F, C60, E60, P60, 60TLR and C60TLR family | 60 HP | 2-Stroke | 1997–2003 examples | 6H3-W0078-02-00 |
| 70B, 70, C70, 70TLR and 70TLR family | 70 HP | 2-Stroke | 1997–2003 examples | 6H3-W0078-02-00 |
| T50, T50TLR and F50-related catalog entries | 50 HP | 2-Stroke | 1998–2003 examples | 6H3-W0078-02-00 |
| T60, T60TLR and T60LB family | 60 HP | 2-Stroke | 2003–2023 catalog entries | 6H3-W0078-02-00 |
| T50, T50TLR and T50LB family | 50 HP | 2-Stroke | 2005–2024 catalog entries | 6H3-W0078-02-00 |
The model families above summarize catalog occurrences and are not a substitute for checking the exact model suffix and serial-number range. Earlier applications may use a different water-pump reference.
Selected Yamaha 4-Stroke Applications
| Model Examples | Rated HP | Stroke | Catalog Years Represented | OEM Reference |
|---|---|---|---|---|
| F50TLHW, F50TLRW | 50 HP | 4-Stroke | 1998 | 6H3-W0078-02-00 |
| F50TLRX | 50 HP | 4-Stroke | 1999 | 6H3-W0078-02-00 |
| F50TLRY | 50 HP | 4-Stroke | 2000 | 6H3-W0078-02-00 |
| F50TLRZ | 50 HP | 4-Stroke | 2001 | 6H3-W0078-02-00 |
| F50TLRA, F50TJRA | 50 HP | 4-Stroke | 2002 | 6H3-W0078-02-00 |
| F50TLRB, F50TJRB | 50 HP | 4-Stroke | 2003 | 6H3-W0078-02-00 |
| F50TLRC | 50 HP | 4-Stroke | 2004 | 6H3-W0078-02-00 |
4-Stroke fitment is limited to the specific catalog applications identified above. Do not assume that every Yamaha 50 HP or 60 HP 4-Stroke or every High Thrust model uses this kit.
Technical Specs
- Product Type
- Water pump repair kit
- Installation
- Direct replacement for the listed applications
- Impeller Material
- Neoprene rubber
- Housing
- Not included in the package described on this page
- Weight
- Approximately 0.65 lb (0.29 kg)
- Finish
- Black impeller-pump components where applicable
What’s in the Box
- 1 × Water pump impeller, 6H3-44352-00-00
- 1 × Woodruff key, 90280-03M03-00
- 1 × Water-pump gasket, 6H3-44315-A0-00
- 2 × Bolt, 97095-08045-00
- 1 × Water-pump gasket, 688-44316-A0-00
- 1 × Outer-plate gasket, 6H3-44324-A0-00
- 1 × Impeller cup, 663-44322-00-00
- 1 × O-ring, 93210-46044-00
- 2 × Bolt, 97395-08055-00
- 1 × Wear plate, 6H3-44323-00-00
Important: A water-pump housing is not included in this package. Aftermarket references such as Sierra 18-3466 may describe a different kit configuration with a housing and should not be used to infer the contents of this product.
Installation Notes
- Disconnect the negative battery cable and remove the engine cover.
- Place a drain pan under the lower unit and drain the gear lubricant according to the engine service procedure.
- Shift the engine into neutral and remove the fasteners securing the lower unit to the midsection.
- Lower the gearcase carefully to expose the water-pump assembly.
- Remove the water-pump housing fasteners and lift the housing from the assembly.
- Record the orientation of the impeller vanes, key, cup, wear plate, and gaskets before removal.
- Remove the old impeller, key, wear plate, cup, and gaskets. Clean all mating surfaces and remove corrosion or old gasket material.
- Install the new components in the correct order. Use an appropriate lubricant during assembly and rotate the driveshaft in the correct direction for the engine so the impeller vanes seat properly.
- Reinstall the pump housing and tighten the fasteners to the manufacturer’s specified torque.
- Reattach the lower unit, ensuring proper alignment of the driveshaft, shift shaft, and water tube.
- Refill the gearcase with the specified lubricant, run the engine with an adequate water supply, and confirm a steady tell-tale stream.
Follow the service manual for your exact engine. If the housing is cracked, warped, deeply grooved, or heavily corroded, inspect it before installation; this kit does not include a replacement housing.
Troubleshooting & FAQ
How do I confirm fitment?
Compare the complete Yamaha model code, rated horsepower, stroke type, production year, shaft configuration, and any applicable serial-number range with the compatibility information above. The reference 6H3-W0078-02-00 appears on multiple model families, but number co-occurrence alone does not confirm every Yamaha application.
Does this kit include a water-pump housing?
No. The package described here includes the impeller, key, gaskets, cup, wear plate, O-ring, and fasteners listed in “What’s in the Box.” Kits sold under other aftermarket references may include a housing, but those are different package configurations.
When should the impeller be replaced?
Replace the impeller according to the maintenance schedule for your engine and whenever it shows cracking, deformation, hardening, missing vanes, or reduced pumping performance. Saltwater, sand, silt, and extended storage can increase service requirements.
What are common signs of a failing water pump?
Symptoms may include a weak or intermittent tell-tale stream, an overheating warning, steam, elevated operating temperature, or reduced water pressure. Stop operation if the engine overheats and inspect the cooling system before further use.
Should I replace the key and wear plate?
Yes. The included key, wear plate, cup, and gaskets are service components intended to be installed with the new impeller. Replacing the related wear parts helps maintain proper impeller drive and sealing.
Is this an OEM part?
No. This is an aftermarket replacement kit intended for applications associated with the listed Yamaha reference numbers. Yamaha is a trademark of its respective owner and is not affiliated with this product.
What if my original housing is damaged?
This kit does not include a housing. Replace the housing separately if inspection finds cracks, distortion, severe corrosion, or grooves that could prevent the impeller from sealing and pumping correctly.
Safety & Important Information
- Verify the complete engine model and year before ordering; horsepower alone is not sufficient for fitment.
- Use the manufacturer’s service manual for torque values, lubricants, assembly direction, and safety procedures.
- Never run an outboard without an adequate water supply.
- This is an aftermarket replacement, not an OEM component.
- Professional installation is recommended when lower-unit service is unfamiliar.
About Sea Sierra
- Marine Replacement Parts — Practical aftermarket components for routine service and repair.
- Application-Focused Listings — Compatibility information is organized by model, horsepower, stroke, and year where available.
- Direct Replacement Value — Service parts supplied for maintenance without representing them as genuine OEM components.
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