Yanmar X0504550-01 Cover Screw
The Yanmar X0504550-01 is the genuine cover screw for Yanmar marine diesel sea water pumps that use this part. It is not ordinary hardware: the grade, the length and the material are chosen for a fastener that lives in salt water and holds a joint that has to stay sealed.
Salt water takes the small hardware first. Heads corrode until a screwdriver or socket no longer grips, threads seize into the housing, and what should be a twenty minute impeller change turns into drilling and retapping. Replacing tired fasteners while they still come out is the cheapest maintenance there is on a raw water pump.
Key Features
- Genuine Yanmar replacement cover screw
- Fits Yanmar marine diesel sea water pumps that use this part
- One per pump
- Correct grade, length and material for a salt water joint
- Replaces corroded, seized or rounded hardware
- Worth keeping spares with the impeller kit
Applications
- Yanmar marine diesel sea water pumps that use this part
- Raw water pump rebuilds and impeller changes
- Replacing corroded or rounded off hardware
- Making up a complete set after a strip down
- Marine installations where salt attacks fasteners first
- Spring commissioning and layup service
Specifications
- Brand: Yanmar
- Manufacturer: Yanmar Marine
- Manufacturer Part Number: X0504550-01
- Part Type: Cover Screw
- Fits: Yanmar marine diesel sea water pumps that use this part
- Quantity Used: One per pump
- Condition: New
Frequently Asked Questions
Q: How tight should cover screws be?
Snug and even in a cross pattern. Overtightening bows the cover, which is one of the most common causes of a pump drawing air.
Q: Is it worth replacing them all at once?
If several are corroded, yes. A mix of new and tired hardware clamps unevenly, and the old ones will need doing at the next service anyway.
Q: Why does the pump hardware corrode faster than the rest of the engine?
It is in the wettest place on the engine, often in contact with a dissimilar metal, and it gets washed with salt water every time the pump is opened.
Q: Can I use a stainless fastener from the hardware store?
It is a gamble. Material, grade and length are all chosen for the joint, and the wrong material in a dissimilar metal housing sets up corrosion that seizes the thread.
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 cover screw.
CLRMarine
