Yamaha F115 Water Pump Impeller Replacement
A worn impeller on your 115 hp Yamaha F115 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 F90
How to Replace a Yamaha Water Pump | F90, F115, & VF115 | DIY Yamaha Outboard Maintenance
Tools Needed
- Screwdriver (thin and flathead)
- Chisel (heavy duty, not too sharp)
- Wrench (7/8")
- Grease
- Rag
Safety
- Avoid taking off the impeller cup housing if possible to prevent damage.
- Be careful when using a chisel to remove the old impeller.
Steps
- Inspect the water pump visually and apply pressure to check for leaks.
- Gently remove the impeller cup housing without damaging it, leaving the cup on.
- Remove the old O-rings from the housing.
- Take off the housing completely if necessary.
- Remove the old impeller, noting the position of the flat washers and wave washer.
- Use a chisel to remove the old impeller keyway pin.
- Install the new oil seal cover, ensuring it sits nicely in place.
- Insert the new impeller into the cup housing, aligning the keyway pin hole.
- Tap the impeller into place using a hammer and a piece of wood or metal.
- Place the flat washers and wave washer onto the impeller shaft, sandwiching the wave washer between the two flat washers.
- Grease the O-ring groove in the housing and slide the housing back onto the impeller.
- Grease the bolts and install them, using a wrench to tighten securely.
- Grab a rag for better grip on the shaft and turn the impeller clockwise while pushing down to ensure a proper seal.
Tips
- Use a whole new water pump kit instead of just replacing the impeller to avoid future issues with rusty or damaged parts.
- Be careful when tapping the impeller into place, ensuring it's flat and properly seated.
Which part do I need for my Yamaha F115?
For most F115 owners the kit above (18-3071) 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 (4)
| Part number | Description | |
|---|---|---|
| 18-3442 | Sierra 18-3442 | Find on Amazon → |
| 6E5-44352-01-00 | 049 | Find on Amazon → |
| 89930 | Impeller | Find on Amazon → |
| 89932 | Impeller Kit | 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 F115 (115 hp)?
The Yamaha F115 (115 hp) uses the impeller sold as 18-3071, plus its OEM and aftermarket cross-references (4 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 F115?
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 115 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 F115, 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 F115?
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 F115 boat valuation
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