Water Pump Repair Kit for Yamaha 9.9HP & 15HP 4-Stroke Outboards — With or Without Housing
Water Pump Repair Kit for Yamaha 9.9HP & 15HP 4-Stroke Outboards — With or Without Housing is backordered and will ship as soon as it is back in stock.
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Water Pump Repair Kit for Yamaha 9.9HP & 15HP 4-Stroke Outboard...
Water Pump Repair Kit for Yamaha 9.9HP & 15HP 4-Stroke Outboards — With or Without Housing is backordered and will ship as soon as it is back in stock.
Product Details
This water pump repair kit is designed for selected Yamaha 9.9HP and 15HP outboard applications. Choose the version that matches your repair: the kit with housing includes a replacement water pump housing, while the kit without housing is intended for engines whose existing housing remains serviceable.
The applicable aftermarket references are Sierra 18-3412 for the version with housing and Sierra 18-3433 for the version without housing. These kits are associated with Yamaha water pump references listed in the part-number matrix below.
- Supports water pump service and cooling-system maintenance.
- Available with or without the water pump housing.
- Includes the primary impeller, wear, sealing and drive components required for the applicable kit version.
- Aftermarket replacement part; not manufactured by Yamaha.
Part Number Matrix
Use the version and reference numbers below to compare the kit with your original water pump assembly before ordering.
| Brand | Part Number | Application or Notes |
|---|---|---|
| Sierra | 18-3412 | Water pump kit with housing. |
| Sierra | 18-3433 | Water pump kit without housing. |
| Yamaha | 63V-W0078-01 | Listed replacement reference for the kit with housing. |
| Yamaha | 63V-44301-00 | Listed replacement reference for the kit with housing. |
| Yamaha | 63V-W0078-01-00 | Listed replacement reference for the kit without housing. |
Engine & Model Compatibility
Catalog information associates these references with the following Yamaha applications. Model, year and stroke conditions should be checked together against the identification plate and the original water pump parts.
| Brand | Model or Application | Rated HP | Stroke | Years Listed | Applicable Kit |
|---|---|---|---|---|---|
| Yamaha | 9.9 / 15 | 9.9 / 15 | 4-Stroke | 1996–2004 | 18-3412 or 18-3433, depending on housing requirement. |
| Yamaha | F15 | 15 | 4-Stroke | 1998–2004 | 18-3412 or 18-3433, depending on housing requirement. |
Important: Do not assume compatibility with every Yamaha 9.9HP or 15HP engine. The catalog application information above is limited to the listed model and year ranges. Verify the complete model designation, year, stroke and original part numbers before purchase.
Technical Specifications
- Product Type
- Water pump repair kit
- Available Versions
- With water pump housing or without water pump housing
- Installation
- Replacement service part for the applicable Yamaha water pump assembly
- Kit With Housing
- Includes a replacement water pump housing together with the applicable pump service components.
- Kit Without Housing
- Includes pump service components for reuse with a serviceable existing housing.
- Construction
- Component materials and finish may vary by part; compare the supplied parts with the original assembly before installation.
What’s in the Box
18-3412 — Version with Housing
- Water pump housing
- Impeller
- Impeller key
- Insert cup
- Wear plate
- Water pump gaskets and sealing components
- Required pump hardware for the applicable kit configuration
18-3433 — Version without Housing
- Impeller
- Impeller key
- Insert cup
- Wear plate
- Water seal and related pump service components
- Required pump hardware for the applicable kit configuration
The two versions are alternatives. The kit without housing does not include the housing shown in the with-housing version.
Installation Notes
- Confirm the complete engine model, year, stroke and kit version before beginning work.
- Disconnect the battery and remove the engine cover as required for access.
- Drain the lower-unit gear lubricant if required by the service procedure.
- Remove the propeller and lower-unit mounting hardware, then carefully separate the lower unit from the driveshaft housing.
- Remove the water pump cover or housing and retain the original parts for comparison.
- Remove the old impeller and note the position of the impeller key before cleaning the shaft and mating surfaces.
- Install the correct gaskets, wear plate, insert cup, key and impeller. Use the with-housing version only when housing replacement is required.
- Reassemble the pump and tighten fasteners according to the Yamaha service specifications for your exact engine.
- Reinstall the lower unit, refill the gear lubricant as specified, and test the cooling-water flow before normal operation.
Follow the service manual for your exact engine. If the housing, driveshaft, keyway or mating surfaces are damaged, correct those conditions before operating the outboard.
Troubleshooting & FAQ
Which version should I choose— with or without housing?
Choose the version with housing when the existing housing is cracked, corroded, warped or otherwise unserviceable. Choose the version without housing only when the existing housing is confirmed to be reusable and the replacement components match your original assembly.
What are the signs of a failing water pump impeller?
Common symptoms include overheating at idle or low speed, weak or absent telltale water flow, reduced cooling performance, or a dry, cracked or brittle impeller during inspection.
How often should the impeller be replaced?
Inspect the water pump components during scheduled maintenance and replace worn or damaged parts. Replacement intervals depend on operating hours, storage and water conditions, especially saltwater or sandy and silty water.
Does this fit all Yamaha 9.9HP and 15HP engines?
No. The listed references are for specific model and year conditions. Confirm the complete model designation, year, 4-stroke configuration and original water pump references before ordering. These references should not be applied to 2-stroke engines without separate confirmation.
Is this an OEM Yamaha part?
No. This is an aftermarket replacement kit. Yamaha part numbers are shown only as manufacturer reference numbers for identification and comparison.
Can I reuse my existing housing with the kit without housing?
Yes, provided the housing is the correct type and is free from cracks, excessive corrosion, distortion and wear. Compare all components before installation; replace the housing if its condition could compromise water-pump performance.
What should I do if the supplied parts do not match my original assembly?
Stop installation and verify the engine model, year, stroke, kit version and original part numbers. Do not force a component into place or operate the engine until compatibility has been confirmed.
Safety & Important Information
- Verify the complete engine model, year, stroke and original part numbers before purchase.
- Do not use the housing-free version when a replacement housing is required.
- Inspect the driveshaft, keyway, housing and mating surfaces during installation.
- Use the torque values and procedures specified for your exact Yamaha engine.
- This is an aftermarket replacement part, not an OEM Yamaha component.
- Professional installation is recommended when lower-unit service experience is limited.
About Sea Sierra
- Marine Replacement Parts — Parts selected for common marine maintenance and repair applications.
- Application-Focused Listings — Model, year and reference information is provided to help you compare the replacement with your original part.
- Support Before Installation — Verify fitment and kit configuration before ordering or beginning service.
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