Water Pump Impeller Kit for Yamaha 150–300 HP Outboards – Replaces 61A-W0078-A4-00, 61A-W0078-A3-00 and 61A-W0078-A2-00
Water Pump Impeller Kit for Yamaha 150–300 HP Outboards – Replaces 61A-W0078-A4-00, 61A-W0078-A3-00 and 61A-W0078-A2-00 is backordered and will ship as soon as it is back in stock.
Worry-free returns
Worry-free returns
Shop with confidence. If you’re not completely satisfied, eligible items may be returned within the return window, provided they are unused and in original packaging.
If the return is due to our error or a defective item, we’ll make it right.
Please contact us before returning any item.
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.
International delivery times may vary due to customs processing.
Tracking information will be provided once your order ships.
Water Pump Impeller Kit for Yamaha 150–300 HP Outboards – Replaces ...
Water Pump Impeller Kit for Yamaha 150–300 HP Outboards – Replaces 61A-W0078-A4-00, 61A-W0078-A3-00 and 61A-W0078-A2-00 is backordered and will ship as soon as it is back in stock.
Product Details
This aftermarket water pump impeller kit is intended for service and replacement applications on selected Yamaha 150–300 HP outboard engines. It is designed to replace water-pump components associated with the Yamaha reference numbers listed below. Always compare the part number, pump design, engine model, year, and serial-number range with your service information before ordering.
The listed Yamaha reference numbers are 61A-W0078-A4-00, 61A-W0078-A3-00, and 61A-W0078-A2-00. Aftermarket cross-reference information may also identify Sierra 18-3396-1 and Mallory 9-48618; these references should be confirmed against the specific engine before installation.
- Installation location: Lower unit/gearcase water pump.
- Product type: Water pump impeller service kit with housing and related pump components.
- Construction: Pump housing is identified as nylon PA66 plastic.
- Application: Selected Yamaha 150–300 HP outboards; exact fitment depends on model, year, stroke, and serial number.
Part Number References
Use the following numbers as reference points when comparing the original water-pump assembly and your engine service documentation. A number match alone does not replace verification of the complete engine application.
| Brand | Part Number | Reference |
|---|---|---|
| Yamaha | 61A-W0078-A4-00 | Listed replacement reference |
| Yamaha | 61A-W0078-A3-00 | Listed replacement reference |
| Yamaha | 61A-W0078-A2-00 | Listed replacement reference |
| Sierra | 18-3396-1 | Aftermarket cross-reference; verify application |
| Mallory | 9-48618 | Aftermarket cross-reference; verify application |
Engine Compatibility
This kit is listed for selected Yamaha outboards in the 150–300 HP range. Because Yamaha water-pump assemblies can vary by model, production year, stroke configuration, and serial-number range, do not rely on horsepower alone to confirm fitment.
| Brand | Listed horsepower range | Application status | Verification required |
|---|---|---|---|
| Yamaha | 150–300 HP | Selected outboard applications | Model, year, stroke, and serial number |
Before purchase, compare the reference number and the original pump components with the engine owner's manual, service manual, or parts diagram. If the housing, insert, impeller, bolt pattern, or keyway differs, do not install the kit.
Technical Specifications
- Product type
- Water pump impeller service kit with housing
- Installation location
- Lower unit/gearcase
- Fitment style
- Replacement service component; confirm exact application before installation
- Housing material
- Nylon PA66 plastic
- Housing color
- Black
- Service function
- Replacement of selected water-pump impeller and related pump components
What’s in the Box
The listed kit contents are:
- 1 × Cartridge insert, reference 61A-44322-02-00
- 1 × Water pump gasket, reference 6E5-44315-A0-00
- 1 × Impeller, reference 6E5-44352-01-00
- 1 × Cartridge outer plate, reference 6G5-44323-01-00
- 4 × Bolts with washers, reference 90119-08M14-00
- 1 × Woodruff key, reference 90280-04M05-00
- 1 × O-ring, reference 93210-37M67-00
- 1 × O-ring, reference 93210-86M38-00
- 2 × Dowel pins, reference 93606-12019-00
Confirm the actual components and quantities against the product packaging before beginning installation.
Installation Notes
- Review the engine service manual and disconnect the battery before starting work. Remove the propeller if required by the service procedure.
- Support the outboard securely and place a suitable drain pan under the lower unit.
- Remove the lower unit according to the manufacturer's procedure, taking care not to damage the driveshaft, shift shaft, or water tube.
- Remove the water-pump housing and note the orientation and order of the original components.
- Clean the mating surfaces and remove old gasket material, debris, and corrosion before assembly.
- Install the replacement gasket, wear or outer plate, cartridge insert, and related components in the correct order.
- Fit the new impeller onto the driveshaft with the Woodruff key fully seated. Confirm the impeller-vane orientation during housing installation.
- Install the housing and fasteners. Use the torque values and tightening sequence specified in the engine service manual.
- Reinstall the lower unit, ensuring correct alignment of the driveshaft, shift shaft, and water tube.
- Refill or check gearcase lubricant only as required by the manufacturer's service procedure.
- Run the engine using an appropriate water supply and confirm a steady tell-tale stream and normal cooling-system operation before returning the engine to service.
Troubleshooting & FAQ
How do I confirm this kit fits my engine?
Compare the listed Yamaha reference number and the complete pump assembly with your engine's service manual or parts diagram. Confirm the model, year, stroke configuration, and serial-number range. The 150–300 HP range alone is not sufficient to establish fitment.
What are common signs of a failing water pump?
Possible symptoms include overheating at idle or low speed, a weak or missing tell-tale stream, an engine-warning alarm, or steam from the cowling. Stop operation if the engine overheats and investigate the cooling system before further use.
How often should the impeller be replaced?
The service interval depends on the engine manufacturer, operating conditions, hours, and storage environment. Follow the maintenance schedule for your specific Yamaha engine and replace the impeller sooner if it has been run dry or shows wear, cracking, distortion, or hardening.
Is this a complete kit with the housing?
The product is listed as a water pump impeller kit with housing and related service components. Review the complete contents list above and compare it with your original assembly before ordering.
Is this an OEM part?
No. This listing is for an aftermarket replacement kit. Yamaha and other brand numbers shown on this page are reference numbers used for application comparison and are not a claim that the product is manufactured by Yamaha, Sierra, or Mallory.
What should I do if the supplied parts do not match?
Do not force the components into place or operate the engine. Stop installation and compare the parts with the engine service documentation and the original pump assembly before contacting support.
Safety & Important Information
- Verify the complete application using the engine model, year, stroke, and serial number before purchase.
- Compare the replacement components with the original pump assembly before installation.
- Use the manufacturer's torque specifications, sealants, lubricants, and installation procedures.
- Never run an outboard without an adequate water supply.
- This is an aftermarket replacement product and is not an OEM component.
- Professional installation is recommended when the lower unit or cooling system is unfamiliar.
About Sea Sierra
- Marine replacement parts: Replacement components for maintenance and repair applications.
- Application-focused listings: Reference numbers and fitment information are provided to help compare the product with your original part.
- Customer support: Contact support with your engine model, year, serial number, and photos of the original component if application assistance is needed.
Payment & Security
Payment methods
Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.
