Yanmar 128620-42201 Impeller for 6CX
The Yanmar 128620-42201 is the factory flexible impeller used in 6CX Series engines. Everything the engine does to stay cool depends on it, and it is the one component in the cooling circuit that is expected to be replaced on a schedule rather than when it fails.
Impellers fail in a way that gives very little warning. The vanes crack at the hub, take a set, or shear off completely, and the first thing most people notice is a high temperature alarm or a thin stream of water at the exhaust. If vanes are missing, find them before running the engine again - they travel downstream and lodge in the heat exchanger, where they block tubes and cause the overheat all over again with a brand new impeller fitted.
Key Features
- Genuine Yanmar replacement flexible impeller
- Fits 6CX 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
- 6CX 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: 128620-42201
- Part Type: Impeller
- Fits: 6CX Series engines
- Quantity Used: One per pump
- Condition: New
Frequently Asked Questions
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.
Q: Do I need to change the wear plate too?
Inspect it. A wear plate with a scored or grooved face lets water slip back past the impeller, so a new impeller against an old plate gives less flow than it should.
Q: Should I fit the impeller dry?
No. Wet it or use a little glycerine, and turn it so the vanes trail in the direction of rotation. That protects the vanes on the first revolution and makes the impeller far easier to fit.
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
