Yamaha F300 Water Pump Impeller Replacement
A worn impeller on your 300 hp Yamaha F300 starves the engine of cooling water and can overheat the powerhead in minutes. Below is the water-pump kit we recommend, which F300 variants it fits, a step-by-step video, and the parts you need to do the job yourself.
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Watch: how to replace it (step by step)
How to replace the water pump impeller on a Yamaha F300
How to Repair a Yamaha Water Pump | F225 – F300 4.2L V6 Models | DIY Yamaha Outboard Maintenance
Tools Needed
- Yamaha F300 water pump repair kit (including impeller, gaskets, plates, bolts, cup, O-rings, and grease)
- Socket wrench
- Grease gun or small brush for applying grease
- Towel or rag to grip splines
Safety
- Ensure the engine is cool before starting any work.
- Be careful not to drop small parts like dowels.
Steps
- Disassemble the water pump by removing the old mounting bolts and cup housing.
- Inspect the old impeller for wear, checking the curl and leading edges.
- Clean the O-ring trough in the cup housing if necessary.
- Install new mounting bolts, cup, and O-rings from the repair kit.
- Place the water pump plate and gasket onto the engine block.
- Align the impeller with the key on the shaft, ensuring it's seated correctly.
- Grease the impeller bolts before installing them.
- Install the impeller by sliding it onto the shaft and pressing down on the plate.
- Grease the seals in the housing and push them into place using a socket.
- Apply grease to the O-ring trough in the cup, filling it generously.
- Snap the cup back into place, ensuring the dowels are flush with the surface.
- Grease the threads of the mounting bolts for the water pump housing.
- Reinstall the water pump housing by turning it clockwise and pressing down simultaneously.
Tips
- Always grease the water pump components to prevent sticking, especially in saltwater environments.
- Keep your engine's serial number and model number handy when ordering parts.
- Use genuine Yamaha parts for optimal performance and engine longevity.
- Be careful not to damage the O-rings during installation.
Which part do I need for my Yamaha F300?
For most F300 owners the kit above (89900) is the right choice — it includes the impeller plus the seals, gaskets and wear plate you should replace at the same time. Price tip: the aftermarket numbers are usually noticeably cheaper than the OEM-branded box — it is the same physical part. If you need an exact match, these compatible part numbers also fit:
Show all compatible part numbers (1)
| Part number | Description | Fits | |
|---|---|---|---|
| 89960 | Impeller for Yamaha F300 | F300 | cross-reference only |
Many of these are the same physical part under different brand numbers (Sierra, GLM, Yamaha OEM). Build years are shown where our parts data has them. Where a variant has no years, only the model code is listed. Confirm the number against your engine plate before ordering.
Frequently asked questions
What water pump impeller fits a Yamaha F300 (300 hp)?
Our parts catalogue lists the Yamaha F300 impeller as 89900, an internal reference no retailer stocks. 1 compatible numbers are listed above. Confirm the number against your engine's model code and year plate before ordering.
How often should I replace the impeller on a Yamaha F300?
Replace the water pump impeller every 1–3 years or roughly every 200–300 running hours, whichever comes first — and sooner if you run in silty, sandy or shallow water where debris wears the vanes faster.
What are the symptoms of a failing impeller on a 300 hp Yamaha?
A weak or missing telltale (pee) stream, engine temperature climbing above normal, or an overheat alarm are the classic warning signs. A worn impeller can overheat and damage the powerhead within minutes, so don't delay the job.
Do I need the full water pump kit or just the impeller?
For the F300, fit the complete kit. The seals, O-rings, gasket and wear plate age alongside the impeller, and replacing them together is the reliable, do-it-once job.
How long does a water pump job take on a Yamaha F300?
For a competent DIYer it's typically a 1–2 hour job of medium difficulty. The step-by-step video above covers every step for this engine.
Related guides
- Yamaha F25 water pump / impeller
- Yamaha F50 water pump / impeller
- Yamaha F70 water pump / impeller
- Yamaha F90 water pump / impeller
- All Yamaha water pump guides
- Free Yamaha F300 boat valuation
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