Yanmar 129470-42532 Impeller for 3JH and 4JH
The Yanmar 129470-42532 is the genuine replacement impeller for 3JH and 4JH Series engines. It is a wear part by design, and the cheapest insurance against an overheat that any engine has.
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 3JH and 4JH 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
- 3JH and 4JH 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: 129470-42532
- Part Type: Impeller
- Fits: 3JH and 4JH Series engines
- Quantity Used: One per pump
- Condition: New
Frequently Asked Questions
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.
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.
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
