Yanmar 128170-42200 Bronze Engine Cooling Pump
Keeping a diesel engine running cool comes down to one hardworking component doing its job quietly in the background, and the Yanmar 128170-42200 is built to do exactly that. This bronze-bodied, flange-mount pump is the OEM replacement raw water pump designed for Yanmar's 1GM and 1GM10 engine series, engineered to move water reliably even after years of continuous service. Its heavy-duty bronze casting resists corrosion in wet environments, while the non-magnetic shaft and long-life mechanical seal are built to handle the demands of regular start-stop use.
What makes this pump especially versatile is the flexible neoprene impeller design, which gives it self-priming capability right out of the box. That means it can pull water into the system on its own rather than relying on gravity or pre-filled lines, a feature that saves time and reduces the guesswork of setup. The impeller and O-ring end seals are also user-replaceable, so routine maintenance doesn't require swapping the entire unit.
While this pump is most commonly installed as an engine cooling pump, its construction and performance make it suitable well beyond that single use case. The same bronze body and impeller design work equally well in bilge pumping, deckwash systems, holding tank evacuation, and general industrial liquid transfer, sump drainage, or handling fluids with light suspended solids. Anyone needing a dependable, self-priming bronze pump for water or mild-chemical transfer will find this a solid, adaptable choice, not just an engine part.
Key Features
- Genuine OEM replacement part number 128170-42200
- Solid bronze pump body for corrosion resistance
- Flexible neoprene impeller for self-priming operation
- Non-magnetic marine-grade stainless steel shaft
- Long-life mechanical seal with O-ring end cover seals
- Flange mount design for direct engine installation
- User-serviceable impeller and seal components
Applications
- Primary raw water/seawater cooling pump for Yanmar 1GM and 1GM10 diesel engines
- Bilge pump applications
- Deckwash and washdown systems
- Holding tank emptying
- General liquid circulation and transfer
- Sump drainage
- Handling of liquids with light suspended solids
- Fresh water, salt water, and mild chemical transfer (not for gasoline or strong solvents/acids)
Specifications
- Material: Bronze body construction
- Impeller: Flexible neoprene
- Shaft: Non-magnetic, marine-grade stainless steel
- Seal type: Mechanical seal with O-ring end covers
- Mount style: Flange mount
- Compatible engines: Yanmar 1GM, 1GM10 series
- Port size: Threaded inlet/outlet ports sized for standard 1GM/1GM10 raw water hose connections; confirm exact port diameter against your engine's service manual before ordering fittings
FAQ Section
Q: Will the Yanmar 128170-42200 fit engines outside the 1GM series?
This pump is designed specifically as a replacement for Yanmar 1GM and 1GM10 diesel engines and is not a direct fit for other Yanmar engine families.
Q: Can this pump run dry for testing purposes?
No. Flexible impeller pumps like this one should never be run dry, even briefly, since the neoprene impeller can overheat and tear without water for lubrication.
Q: How often should the impeller be replaced?
Impeller life depends on usage, but many owners inspect it annually and replace it every one to two seasons, or sooner if reduced water flow is noticed.
Q: Is this pump reversible in rotation direction?
Flexible impeller pumps of this design are typically rotation-specific, so it should be installed to match the original rotation direction of the engine it replaces.
Q: Can this pump handle chemicals other than water?
It is compatible with fresh water, salt water, and mild chemical solutions, but should not be used with gasoline, strong solvents, or acids, which can damage the neoprene impeller.
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