Yanmar 2QM15 Water Pump Impeller Replacement
A worn impeller on your Yanmar 2QM15 starves the engine of cooling water and can overheat it 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 – Yanmar 2QM15
Yanmar 2QM15 raw water impeller service
Tools Needed
- Machine screws (M4x8)
- Hilum (a type of lubricant)
- Gasket (Part number: 1042142090)
Safety
- Ensure the engine is turned off and cool before starting any work.
- Wear appropriate safety gear, including gloves and safety glasses.
Steps
- Undo the bolts and remove the back plate, ensuring not to move the wheel.
- Take a photo of the back plate to remember the orientation of the arms.
- Apply a super thin coating of Hilum to the back of the new gasket.
- Place the new gasket on the back plate.
- Position the impeller pump back into the raw water pump.
- Attach the hoses first, then put the bolts on super loose.
- Use a spanner to tighten the bolts until they are snug.
- Reattach the zinc and thermostat at the front of the engine.
Tips
- When taking the back plate off, hold it just like in the video to see the orientation of the arms.
- Take a photo of the back plate before removing it to remember the orientation of the arms.
- Keep the old impeller and gasket as spares.
Which part do I need for my Yanmar 2QM15?
For most 2QM15 owners the part above (104211) is the right choice.
Frequently asked questions
What water pump impeller fits a Yanmar 2QM15?
The Yanmar 2QM15 uses the impeller sold as 104211. Confirm the number against your engine's model code and year plate before ordering.
How often should I replace the impeller on a Yanmar 2QM15?
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.
What are the symptoms of a failing impeller on a Yanmar 2QM15?
A weak or missing telltale stream, engine temperature climbing above normal, or an overheat alarm are the classic warning signs. A worn impeller can overheat and damage the engine within minutes, so don't delay the job.
Do I need the full water pump kit or just the impeller?
For the 2QM15, 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 Yanmar 2QM15?
For a competent DIYer it's typically a 1-2 hour job of medium difficulty. The step-by-step video above covers every step.
Related guides
- Yanmar 3GM30F water pump / impeller
- Yanmar 2GM20F water pump / impeller
- Yanmar 3GM30 water pump / impeller
- Yanmar 2GM20 water pump / impeller
- All Yanmar water pump guides
- Free Yanmar boat valuation
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