Yanmar 128628-42203 Impeller for 6CX
The Yanmar 128628-42203 is the genuine flexible impeller for 6CX Series engines. It is the single part that moves raw water through the engine: rubber vanes bend as they sweep past the cam inside the pump body, opening behind to draw sea water in and closing ahead to push it out to the heat exchanger and the exhaust.
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: 128628-42203
- Part Type: Impeller
- Fits: 6CX Series engines
- Quantity Used: One per pump
- Condition: New
Frequently Asked Questions
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.
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.
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
