Yanmar 1GM10 Water Pump Impeller Replacement
A worn impeller on your Yanmar 1GM10 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.
Check today’s price on Amazon →
Watch: how to replace it (step by step)
How to Replace Impeller – Yanmar 1GM10
Yanmar 1GM10 water pump rebuild
Tools Needed
- 13mm socket
- Screwdriver
- Wooden blocks
- 3-in-1 oil
Safety
- Wear safety glasses to protect your eyes from debris.
- Be cautious when using tools to avoid damaging components.
Steps
- Clean the pump body using a weak solution of caustic soda (drain cleaner), monitoring every 10 minutes.
- Install the new O-ring on the pump body to seal it from the engine.
- Press fit the first seal into the pump body, ensuring the lip faces out towards the impeller.
- Install the second seal, ensuring it is flush with the lip where the bearing sits.
- Insert the first bearing, then the circlip, followed by the second bearing and the circlip.
- Lubricate the shaft with 3-in-1 oil and insert it through the bearings and seals.
- Install the new impeller, ensuring it is clean and all blades are present.
Tips
- Use a 13mm socket to press fit the seals into the pump body.
- Be gentle when inserting the bearings to avoid damaging the inner race.
- Ensure the impeller is clean and all blades are present before installation.
Which part do I need for my Yanmar 1GM10?
For most 1GM10 owners the part above (128176) is the right choice.
Frequently asked questions
What water pump impeller fits a Yanmar 1GM10?
The Yanmar 1GM10 uses the impeller sold as 128176. Confirm the number against your engine's model code and year plate before ordering.
How often should I replace the impeller on a Yanmar 1GM10?
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 1GM10?
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 1GM10, 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 1GM10?
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
As an Amazon Associate we earn from qualifying purchases — at no extra cost to you. Prices and availability are shown at checkout. This guide is for reference; always follow the engine manufacturer’s service manual.