Yanmar 129470-42540 Wear Plate for 3JH and 4JH
The Yanmar 129470-42540 is the factory wear plate used in 3JH and 4JH Series engines. It gives the impeller a hard, flat sealing face on one side of the pumping chamber, and it is deliberately the cheapest part in that stack.
A wear plate fails by being scored. Grit, sand and the occasional piece of shell go through the pump with the raw water, and each pass leaves a fine scratch until the face carries a set of circular grooves. Those grooves are leak paths: water carried round by the vanes slips back across the plate instead of going out of the discharge, and flow drops even though the impeller is new.
Key Features
- Genuine Yanmar replacement wear plate
- Fits 3JH and 4JH Series engines
- One per pump
- Restores the flat sealing face the impeller runs against
- Recovers flow lost to a scored or pitted plate
- Sacrificial part that protects the pump body
Applications
- 3JH and 4JH Series engines
- Raw water pump rebuilds and impeller changes
- Restoring flow after a new impeller did not fix the problem
- Service on a pump that has passed sand or grit
- Repairing corrosion damage inside the pump body
- Spring commissioning and layup service
Specifications
- Brand: Yanmar
- Manufacturer: Yanmar Marine
- Manufacturer Part Number: 129470-42540
- Part Type: Wear Plate
- Fits: 3JH and 4JH Series engines
- Quantity Used: One per pump
- Condition: New
Frequently Asked Questions
Q: Why does the plate wear at all?
Everything the strainer lets through goes between the impeller vanes and the plate. Sand and grit are abrasive, and over a season they polish a set of grooves into the face.
Q: Does it matter which way round it goes?
Yes. One face is the running face and it carries the wear pattern. Note the orientation before removing it, and fit a new plate the same way round.
Q: Can I turn the old plate over and reuse it?
It is not designed to be reversible, and the back face is not finished to run against an impeller. Fit a new one.
Q: Is it worth replacing with every impeller?
Inspect with every impeller and replace when it is marked. On a boat that picks up sand or shell, that often works out to every second impeller.
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 wear plate.
CLRMarine
