Engine Cooling Pump – Fits Yanmar 2GMF, 3GMF, 2YM, 3YM (Replaces 128397-42500)

$252.50 $404.00

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Engine Cooling Pump – Fits Yanmar 2GMF, 3GMF, 2YM, 3YM (Replaces 128397-42500) is backordered and will ship as soon as it is back in stock.

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Product Details

This aftermarket Engine Cooling Pump – Fits Yanmar 2GMF, 3GMF, 2YM, 3YM (Replaces 128397-42500) is designed for a range of Yanmar marine diesel engines, including the 2GMF, 3GMF, 2YM, and 3YM series. It is compatible with various model years, including European-built YEU models from 1996–2004.

It serves as a direct replacement for Yanmar part numbers 128397-42500 and 128990-42500, and interchanges with Johnson pump models 10-24509-01, 10-13337-01, and F4B-903.

Engine-mounted bracket installation for secure fitting.
Durable bronze housing offers superior corrosion resistance in marine environments.
Includes the essential steel pulley with washer and nut for a complete installation.

Part Number Matrix

Use this matrix to confirm equivalent references across OEM and aftermarket.

Brand	Part Number	Notes
Yanmar	128397-42500	Primary OEM reference
Yanmar	128990-42500	Superseded part number
Johnson	10-24509-01	Aftermarket cross-reference
Johnson	10-13337-01	Aftermarket cross-reference
Johnson	F4B-903	Aftermarket cross-reference

Engine & Model Compatibility

Confirm your engine model/year in the table below.

For Yanmar YEU series, this pump fits European-built models with serial numbers starting with 'E'.

Brand	Model	Rated HP	Years	OEM Part No.	Notes
Yanmar	2GMF			128397-42500	Raw water engine cooling pump
Yanmar	3GMF			128397-42500	Raw water engine cooling pump
Yanmar	2GM20F-YEU		1996–2004	128397-42500	European-built models (Serial number starts with 'E')
Yanmar	3GM30F-YEU		1996–2004	128397-42500	European-built models (Serial number starts with 'E')
Yanmar	2YM15	15	Early models	128397-42500	Indirect cooled engines
Yanmar	3YM20	20	Early models	128397-42500	Indirect cooled engines
Yanmar	3YM30	30	Early models	128397-42500	Indirect cooled engines

Technical Specs

Product Type: Raw Water / Seawater Engine Cooling Pump
Installation: Engine-mounted with bracket
Connection: 3/8 inch hose ports (inlet and outlet)
Housing Material: Bronze
Housing Color: Bronze
Dimensions: 19.0" x 16.0" x 14.5" (L x W x H)
Weight: 1.82 kg (4.0 lbs)
Fitting Type: Hose connection
Warranty: 1 Year Manufacturer's Warranty
Other Technical Attributes: Bronze construction, Neoprene impeller, Heavy duty marine grade casting, 3X series non-magnetic marine grade shaft, Long life mechanical seal, O-Ring seals on end covers

What’s in the Box

1 x Engine Cooling Pump Assembly (128397-42500)
1 x Mounting Bracket
1 x Steel Pulley (Washer & Nut included)

Installation Notes

Ensure the engine is completely cool and disconnect the battery.
Close the raw water seacock to prevent water from entering the vessel.
Place a catch pan under the existing pump to manage spills.
Loosen the belt and remove it from the pump pulley.
Disconnect the inlet and outlet hoses from the old pump. Note their orientation.
Unbolt and remove the old pump assembly from the engine bracket.
Clean the mounting surface to ensure a proper seal.
Mount the new pump assembly and tighten the bolts to the engine manufacturer's torque specifications.
Reconnect the hoses and secure them with appropriate marine-grade clamps.
Reinstall and tension the belt according to your engine's service manual.
Open the seacock and reconnect the battery.
Start the engine and immediately inspect for any water leaks at the pump body and hose connections.

Troubleshooting & FAQ

How do I confirm this pump fits my engine?

This pump is designed for Yanmar 2GMF, 3GMF, 2YM, and 3YM series engines. For 2GM20F-YEU and 3GM30F-YEU models (1996–2004), confirm your engine serial number begins with an 'E'. The most reliable method is to cross-reference your existing part number with those listed in our Part Number Matrix.

What are the signs my current pump is failing?

Common signs of a failing raw water pump include the engine overheating, visible water leaks from the pump body or seals, a noticeably reduced flow of water from the exhaust outlet, or unusual grinding/whining noises coming from the pump during operation.

Can I just replace the impeller instead of the whole pump?

Yes, the neoprene impeller is a standard service item. However, if the pump housing is scored, the shaft is worn, or the seals are leaking, replacing the entire pump assembly is the most reliable solution to prevent recurring issues and ensure long-term performance.

What is the difference between this pump and the original Yanmar part?

This is a high-quality aftermarket pump engineered to meet or exceed OEM specifications. It features a heavy-duty bronze casting, a non-magnetic marine-grade shaft, and a long-life mechanical seal for durability, offering a cost-effective and reliable alternative to the original component.

What maintenance does this pump require?

It is best practice to inspect the impeller for cracks, stiffness, or wear at least once a year, typically during winterization or pre-season commissioning. Also, periodically check for any leaks around the seals and ensure hose connections remain tight and free of corrosion.

How can I tell if my Yanmar has a "YEU" European model?

Yanmar engines built in the European Union (YEU) are identified by a serial number that starts with the letter 'E'. This pump is confirmed to fit those specific models from 1996–2004.

OEM vs. Aftermarket?

This listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.

Shipping speed & cost

We ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.

Warranty & returns

Covered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused & in original condition). See our policy page or reach out for instructions.

Safety & Important Info

Verify images/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.
This is an aftermarket replacement, not an OEM component.
Professional installation is recommended for safety and performance.

About Sea Sierra

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