Yanmar 127610-42270 Impeller for 4LH and 4LHA
The Yanmar 127610-42270 is the genuine replacement impeller for 4LH, 4LHA and 6BY Series engines. It is a wear part by design, and the cheapest insurance against an overheat that any engine has.
Dry running is what kills them quickly. A closed seacock, a blocked strainer or an air lock leaves the vanes flexing against the cam with nothing to lubricate or cool them, and seconds of that is enough to glaze or shear the rubber. Everything else is age: rubber hardens, takes a set in the shape it was parked in, and stops sealing against the cam even though it still looks serviceable.
Key Features
- Genuine Yanmar replacement flexible impeller
- Fits 4LH, 4LHA and 6BY Series engines
- One per pump
- Restores raw water flow and cooling capacity
- Molded to the factory vane profile for correct flex life
- A scheduled service item, not a run to failure part
Applications
- 4LH, 4LHA and 6BY Series engines
- Scheduled annual or seasonal impeller changes
- Restoring cooling after a high temperature alarm
- Recovering an engine that was run with a closed seacock
- Spring commissioning and winter layup service
- Spares kept aboard for offshore passages
Specifications
- Brand: Yanmar
- Manufacturer: Yanmar Marine
- Manufacturer Part Number: 127610-42270
- Part Type: Impeller
- Fits: 4LH, 4LHA and 6BY Series engines
- Quantity Used: One per pump
- Condition: New
Frequently Asked Questions
Q: Can I carry a spare for years?
Yes, if it is stored in its packaging, out of sunlight and away from heat. What ages rubber on the shelf is light, heat and being left compressed.
Q: How often should the impeller be changed?
Follow the engine service schedule, and in practice once a season for a boat in regular use. Age matters as much as hours, because the rubber hardens and takes a set whether the engine runs or not.
Q: Some vanes are missing. What now?
Account for every one before the engine runs again. Missing pieces travel to the heat exchanger and block tubes, which causes the same overheat with a new impeller fitted.
Q: Why did the impeller fail so quickly?
Almost always dry running - a closed seacock, a blocked strainer or a collapsed intake hose. The raw water is what lubricates and cools the vanes against the cam.
Not sure this is the right part? Send us a Picture of the Pump Plate on your pump and the CLR Marine team will confirm the correct impeller.
CLRMarine
