Water Pump Service Kit with Housing for Yamaha C55 2-Stroke, 1990–1994 – OEM Reference 663-W0078-00
Water Pump Service Kit with Housing for Yamaha C55 2-Stroke, 1990–1994 – OEM Reference 663-W0078-00 is backordered and will ship as soon as it is back in stock.
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Water Pump Service Kit with Housing for Yamaha C55 2-Stroke, 1990–1...
Water Pump Service Kit with Housing for Yamaha C55 2-Stroke, 1990–1994 – OEM Reference 663-W0078-00 is backordered and will ship as soon as it is back in stock.
Product Details
This aftermarket water pump service kit with housing is designed for Yamaha C55 2-stroke outboard engines from model years 1990 through 1994. It is intended for water pump service when the impeller, sealing components, wear components, and pump housing require replacement.
The company product record identifies this as a service kit supplied with housing. The listed Yamaha OEM reference is 663-W0078-00. Please compare the original water pump assembly and reference number before ordering, because fitment depends on the exact engine model and year.
- Complete water pump service kit with housing for the specified Yamaha C55 application.
- Includes service components intended to renew the water pump assembly and restore cooling-water circulation.
- Aftermarket replacement component; Yamaha is referenced for application and part-number identification only.
Part Number Information
Use the following reference when confirming the correct water pump service kit for your engine.
| Brand | Reference | Application note |
|---|---|---|
| Yamaha Outboard | 663-W0078-00 | Water pump service kit with housing |
Engine Compatibility
This listing is specifically for the following application:
| Brand | Model | Rated HP | Stroke | Model years | Housing reference |
|---|---|---|---|---|---|
| Yamaha | C55 | 55 HP | 2-Stroke | 1990–1991 | 663-W0078-00 |
| Yamaha | C55 | 55 HP | 2-Stroke | 1992–1994 | 663-W0078-00 |
Important: Do not assume compatibility with other Yamaha horsepower ratings, C55 variants, 4-stroke engines, or other model years solely because a similar water pump reference appears in another catalog. Confirm the complete model designation, year, original housing, and part-number reference before purchase.
Technical Specifications
- Product type
- Water pump service kit with housing
- Brand application
- Yamaha Outboard
- Engine model
- C55
- Engine output
- 55 HP
- Engine stroke
- 2-Stroke
- Applicable years
- 1990–1994
- Housing included
- Yes
- Product status
- Aftermarket replacement
What’s in the Box
This product is supplied as a water pump service kit with housing. The kit includes the housing and the service components supplied for the specified application. Component appearance and exact included hardware may vary by production batch, so compare the package contents with the product image and your original assembly before installation.
- 1 x Water pump housing
- Water pump service components for the Yamaha C55 application
- Replacement fasteners as supplied with the kit
Installation Notes
- Disconnect the battery and place the outboard in neutral before beginning work.
- Remove the lower unit according to the engine manufacturer's service procedure.
- Remove the original water pump cover and housing, then take out the old impeller and related service components.
- Clean gasket surfaces and inspect the driveshaft, water pump plate, water tube, and surrounding components for corrosion, scoring, or damage.
- Install the new service components and housing in the same orientation as the original assembly. Make sure the impeller vanes and key are correctly positioned if applicable to the engine assembly.
- Use the supplied fasteners only where they match the original hardware and tighten all fasteners to the manufacturer's specified torque.
- Reinstall the lower unit, ensuring correct alignment of the driveshaft, shift shaft, and water tube.
- Run the engine using an appropriate water supply and confirm a steady tell-tale stream before returning the boat to service.
Maintenance & Troubleshooting
What indicates a water pump service may be needed?
A weak or missing tell-tale stream, an overheating warning, steam, or visible deterioration of the impeller and housing can indicate a cooling-system problem. Stop the engine if it overheats and inspect the water pump before continued operation.
Does this kit include the housing?
Yes. The company product specification identifies this item as a Yamaha 2-stroke water pump service kit with housing.
Will this fit another Yamaha engine?
The confirmed application for this listing is the Yamaha C55 2-stroke from 1990 through 1994. Other models, horsepower ratings, strokes, and years are not confirmed by the company fitment record. Verify the original part reference and housing before ordering.
Is this an OEM Yamaha part?
No. This is an aftermarket replacement. Yamaha and reference 663-W0078-00 are used only to identify the intended application and corresponding reference.
Safety & Important Information
- Verify the exact Yamaha model, year, stroke, and original water pump housing before purchase.
- Compare the product image and supplied components with your existing assembly before installation.
- Use proper marine-service procedures and follow the engine manufacturer's torque and safety instructions.
- Professional installation is recommended if you are not experienced with lower-unit or water-pump service.
About Sea Sierra
- Marine replacement parts — Practical aftermarket components for routine outboard maintenance and repair.
- Application-focused listings — Fitment information is provided by model, year, horsepower, and stroke where available.
- Service support — Contact support if you need help comparing your original water pump assembly with this application.
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