Water Pump Repair Kit – Fits Yamaha F300/F350 300-350 HP (Replaces Yamaha 6AW-W0078-00, Sierra 18-3477)
Water Pump Repair Kit – Fits Yamaha F300/F350 300-350 HP (Replaces Yamaha 6AW-W0078-00, Sierra 18-3477) 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 Repair Kit – Fits Yamaha F300/F350 300-350 HP (Replaces ...
Water Pump Repair Kit – Fits Yamaha F300/F350 300-350 HP (Replaces Yamaha 6AW-W0078-00, Sierra 18-3477) is backordered and will ship as soon as it is back in stock.
Product Details
This Water Pump Repair Kit – Fits Yamaha F300/F350 Outboard Motors (Replaces 6AW-W0078-00) is designed for Yamaha 4-Stroke outboard motors from 300–350 HP, specifically models F300, F350, LF300, and LF350 manufactured between 2007 and 2011. It provides all necessary components for a complete and reliable water pump service to restore cooling system performance.
It serves as a direct replacement for Yamaha part numbers 6AW-W0078-00, 6AW-W0078-00-00, and Sierra 18-3477.
- Engineered for a direct OEM factory replacement fit.
- Kit includes a new impeller, gaskets, O-rings, and all required hardware for a full rebuild.
- Note: This kit is for use with water pump housing 6AW-44311-01-00 (sold separately).
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Yamaha | 6AW-W0078-00 |
| Yamaha | 6AW-W0078-00-00 |
| Sierra | 18-3477 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Yamaha | F300 | 300 | 4-Stroke | 2007–2011 | 6AW-W0078-00 | V8 Engine |
| Yamaha | LF300 | 300 | 4-Stroke | 2007–2011 | 6AW-W0078-00 | Counter-Rotation V8 |
| Yamaha | F350 | 350 | 4-Stroke | 2007–2011 | 6AW-W0078-00 | V8 Engine |
| Yamaha | FL350 | 350 | 4-Stroke | 2007–2011 | 6AW-W0078-00 | Counter-Rotation V8 |
| Yamaha | LF350 | 350 | 4-Stroke | 2007–2011 | 6AW-W0078-00 | Counter-Rotation V8 |
| Yamaha | F350TUR | 350 | 4-Stroke | 2010–2011 | 6AW-W0078-00 | V8 Engine |
Technical Specs
- Product Type
- Water Pump Repair Kit
- Installation
- OEM Factory Direct Replacement
- Other Technical Attributes
- For use with water pump housing 6AW-44311-01-00 (sold separately)
What’s in the Box
- 1 x Gasket, Water Pump (6AW-44315-00-00)
- 1 x Insert, Cartridge (6AW-44322-00-00)
- 1 x Outer Plate, Cartridge (6AW-44323-00-00)
- 1 x Key (6AW-44336-00-00)
- 1 x Impeller (6AW-44352-00-00)
- 4 x Bolt, With Washer (90119-08M14-00)
- 1 x O-Ring (93210-37M67-00)
- 1 x O-Ring (93210-94003-00)
- 2 x Pin, Dowel (93606-12019-00)
Installation Notes
- Disconnect the battery and ensure the engine is in a safe, stable position.
- Drain the lower unit gear case oil.
- Remove the lower unit (gear case) from the outboard motor.
- Unbolt and remove the existing water pump housing.
- Carefully inspect the housing for wear, scoring, or warping. Replace if damaged.
- Remove the old impeller, gaskets, plates, and seals. Clean all mating surfaces thoroughly.
- Install the new components from the kit in the reverse order of removal. Lightly grease the new impeller and insert.
- Reinstall the water pump housing, ensuring bolts are tightened to the manufacturer's specified torque.
- Reattach the lower unit to the outboard, refill the gear case oil, and reconnect the battery.
- Start the engine in a safe environment with a water supply (flushing muffs) to verify proper water flow and check for leaks.
Troubleshooting & FAQ
How do I know if this kit fits my specific Yamaha outboard?
This kit is specifically for the Yamaha F300, LF300, F350, and LF350 (300–350 HP) V8 models made between 2007 and 2011. Always verify your engine model and year against the compatibility table. Do not purchase if your model is not listed.
Is the water pump housing included in this kit?
No, the water pump housing (part number 6AW-44311-01-00) is not included and must be purchased separately. It is critical to inspect your existing housing for wear, cracks, or warping and replace it if necessary for a successful repair.
What are the signs of a failing water pump impeller?
Common symptoms include a weak or intermittent water stream from the "tell-tale" port, engine overheating alarms, and reduced engine performance. A visual inspection may reveal cracked, brittle, or missing impeller vanes.
What is the recommended replacement interval for the water pump kit?
As a preventative maintenance measure, most marine mechanics recommend replacing the water pump impeller and related components every 1-2 years or every 100-200 hours of operation, depending on usage conditions (e.g., saltwater vs. freshwater).
OEM vs. Aftermarket?
This listing is an aftermarket replacement (not OEM). It has been built to OEM-level specifications with comparable materials. All our parts are manufactured in an ISO 9002 facility and are batch-inspected for consistency and quality.
Shipping speed & cost
We ship worldwide quickly—typical transit is 5–15 days. Standard shipping is free; expedited options will appear at checkout where available for your location.
Warranty & returns
This product is covered by a 1-year warranty against manufacturing defects under normal use. If any issues arise, contact our support team with your order details. Returns are accepted within our standard window, provided the item is unused and in its original condition. Please see our full policy page or reach out for instructions.
Safety & Important Info
- Verify images/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.
- This is an aftermarket replacement, not an OEM component.
- Professional installation is recommended for safety and performance.
About Sea Sierra
- Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.
- Fast Global Fulfillment — Free standard delivery to most regions in 5–15 days.
- Manufacturer-Direct Value — Fair pricing without compromising on materials or QC.
Payment & Security
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