Yamaha F25 Water Pump Impeller Replacement
A worn impeller on your 25 hp Yamaha F25 starves the engine of cooling water and can overheat the powerhead in minutes. Below is the exact water-pump kit that fits this engine, 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 Impeller – Yamaha F25
How to change damaged Yamaha 25hp outboard impeller
Tools Needed
- Screwdriver (size number 10)
- Screwdriver (size number 12)
Safety
- Ensure the motor is tilted properly to access the impeller.
- Be cautious when handling the impeller and housing to avoid damage.
Steps
- Remove the four screws (size number 10 and 12) securing the impeller housing.
- Gently lift off the impeller housing, tilting the motor if necessary.
- Inspect the impeller housing for any signs of damage or wear.
- Remove the old impeller from the housing.
- Clean the housing if necessary to remove any debris or residue.
- Align the new impeller correctly, ensuring the keyhole is facing down.
- Gently insert the new impeller into the housing, spinning it to ensure a proper fit.
- Apply a small amount of lubricant to the impeller and housing for smooth operation.
- Reattach the impeller housing, ensuring all screws are securely tightened.
Tips
- Ensure the impeller is not damaged or worn before reinstalling.
- Properly align the impeller before inserting it into the housing to avoid damage.
Which part do I need for my Yamaha F25?
For most F25 owners the kit above (18-3068) 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 (15)
| Part number | Description | |
|---|---|---|
| 18-3071 | Sierra 18-3071 | Find on Amazon → |
| 18-3395 | Sierra 18-3395 | Find on Amazon → |
| 18-3396-1 | Sierra 18-3396-1 | Find on Amazon → |
| 18-3432 | Sierra 18-3432 | Find on Amazon → |
| 18-3443 | Sierra 18-3443 | Find on Amazon → |
| 18-3515 | Sierra 18-3515 | Find on Amazon → |
| 6E5-44352-01-00 | 049 | Find on Amazon → |
| 6H4-44352-02-00 | 052 | Find on Amazon → |
| 6L5-44352-00-00 | 052 | Find on Amazon → |
| 89300 | Impeller | Find on Amazon → |
| 89900 | Impeller | Find on Amazon → |
| 89930 | Impeller | Find on Amazon → |
| 89932 | Impeller Kit | Find on Amazon → |
| 8M6012787 | Mercury OEM 8M6012787 (replaces Sierra 18-3396-1) | Find on Amazon → |
| 8M6012788 | Mercury OEM 8M6012788 (replaces Sierra 18-3395) | Find on Amazon → |
Many of these are the same physical part under different brand numbers (Sierra, GLM, Yamaha OEM). Confirm the number against your engine plate before ordering.
Frequently asked questions
What water pump impeller fits a Yamaha F25 (25 hp)?
The Yamaha F25 (25 hp) uses the impeller sold as 18-3068, plus its OEM and aftermarket cross-references (15 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 F25?
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 25 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 F25, 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 F25?
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 F50 water pump / impeller
- Yamaha F70 water pump / impeller
- Yamaha F90 water pump / impeller
- Yamaha F115 water pump / impeller
- All Yamaha water pump guides
- Free Yamaha F25 boat valuation
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