Yanmar 104211-42120 Retainer Cover for 2GM and 3GM
The Yanmar 104211-42120 is the genuine replacement retainer cover for the sea water pump fitted to 2GM and 3GM Series engines. It is a simple part whose flatness has a direct effect on how much water the pump can move.
Covers go out of shape. Repeated overtightening bows the plate between its screws, and once it is bowed it no longer bears evenly on its seal or presents a flat face to the impeller. The symptom is a pump that draws air instead of water - weak exhaust flow, slow priming, and an engine that runs warm while the strainer and the seacock are demonstrably clear.
Key Features
- Genuine Yanmar replacement retainer cover
- Fits the sea water pump fitted to 2GM and 3GM Series engines
- One per pump
- Restores a flat sealing face for the impeller
- Replaces a distorted, pitted or corroded cover
- Renew the cover seal at the same time
Applications
- the sea water pump fitted to 2GM and 3GM Series engines
- Raw water pump rebuilds and impeller changes
- Curing air being drawn in at the cover joint
- Replacing a cover bowed by overtightening
- Repairing corrosion damage on a pump that has seen years of salt water
- Spring commissioning and layup service
Specifications
- Brand: Yanmar
- Manufacturer: Yanmar Marine
- Manufacturer Part Number: 104211-42120
- Part Type: Retainer Cover
- Fits: The sea water pump fitted to 2GM and 3GM Series engines
- Quantity Used: One per pump
- Condition: New
Frequently Asked Questions
Q: Does the cover affect how much water the pump moves?
Directly. It is one of the two faces the impeller vanes seal against, so a pitted or bowed cover lets water slip back inside the pump instead of leaving the discharge.
Q: How do I tell if the cover is distorted?
Lay it on something known to be flat and look for daylight under the edges, particularly between the screw holes. A bowed cover will not seal and will not present a flat face to the impeller.
Q: My pump draws air rather than water. Could the cover be the cause?
It is one of the first places to look, along with the cover seal and the intake hose. Air drawn in at the cover joint gives a weak exhaust stream with a perfectly clear strainer.
Q: How tight should the cover screws be?
Snug and even, in a cross pattern. Overtightening is what bows the cover in the first place, and a bowed cover leaks however hard it is done up.
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 retainer cover.
CLRMarine
