Major Rebuild Kit – Fits Yanmar 2GM, 3GM Series (Replaces 128377-42500, 128397-42500)

Major Rebuild Kit – Fits Yanmar 2GM, 3GM Series (Replaces 128377-42500, 128397-42500)Major Rebuild Kit Fits Yanmar 2GM, 3GM Series (Replaces 128377 42500, 128397 42500) This high quality sea water pump major rebuild kit is designed for specific Yanmar marine diesel engines. It is engineered to fit the GM YEU European built series manufactured between 1996 and 2004, which are identifiable by an E prefix serial number. This kit serves as a direct replacement for several Yanmar and Johnson part numbers, ensuring a precise fit and

Major Rebuild Kit – Fits Yanmar 2GM, 3GM Series (Replaces 128377-42500, 128397-42500)

This high-quality sea water pump major rebuild kit is designed for specific Yanmar marine diesel engines. It is engineered to fit the GM-YEU European-built series manufactured between 1996 and 2004, which are identifiable by an E-prefix serial number.

This kit serves as a direct replacement for several Yanmar and Johnson part numbers, ensuring a precise fit and reliable performance for compatible sea water pumps.

• Installation: Direct OEM-style replacement for a straightforward installation.
• Compatibility: Designed specifically for pumps with a 6-bolt cover measuring 76mm (3") in diameter.
• Complete Kit: Includes all necessary components for a major overhaul, such as the impeller, bearings, seals, O-rings, and end cover.

Part Number Cross-Reference

Use this table to confirm equivalent part numbers across OEM and aftermarket brands.

Compatible Engine Models

Confirm your engine model/year in the table below.

Technical Specifications

Package Contents

• 1 x Water Pump Impeller (128991-42200/128990-42200)
• 1 x Pump End Cover O-ring (X02173476)
• 1 x Slinger O-ring (X02173432)
• 1 x Retaining Ring (X00370012)
• 1 x Retaining Ring (X00371732)
• 1 x Spacer Plate (X0145050)
• 1 x Bearing (X03431760)
• 1 x Bearing (X03431748)
• 1 x SS Screws Set (X0504163)
• 1 x Lip Seal (X02233010)
• 1 x End Cover (X0142398/128990-42540)

Installation Guide

1. Safety First: Before starting, ensure the engine is off and cool. Close the sea cock to prevent water from entering the boat.
2. Access the Pump: Locate the sea water pump on the engine and remove any guards or hoses blocking access. Place a rag underneath to catch any spilled coolant.
3. Remove the Old Pump Cover: Unscrew the six bolts holding the end cover in place. Carefully pry off the cover.
4. Extract the Old Impeller: Using pliers or an impeller puller tool, remove the old impeller from the pump housing.
5. Disassemble the Pump: Remove the retaining rings, bearings, and seals from the pump housing. Note their orientation for reassembly.
6. Clean and Inspect: Thoroughly clean the pump housing, cover, and all contact surfaces. Inspect for any cracks, scoring, or excessive wear.
7. Install New Components: Install the new bearings, lip seal, and retaining rings from the kit in the reverse order of disassembly.
8. Install the New Impeller: Lightly lubricate the new impeller and housing interior with a suitable marine lubricant. Insert the new impeller, bending the blades in the correct rotational direction.
9. Install the New Cover: Place the new gaskets/O-rings and install the new end cover. Secure it with the new stainless steel screws, tightening them in a star pattern to ensure an even seal.
10. Final Checks: Reconnect all hoses. Open the sea cock. Start the engine and immediately check for any leaks around the pump.

Troubleshooting & FAQ

Q: How do I confirm this kit fits my engine?

A: This kit is specifically for the European-built Yanmar 2GM-YEU and 3GM-YEU series engines manufactured between 1996 and 2004. A key identifier is an "E" prefix on your engine's serial number. The pump this kit services has a 6-bolt cover with a 76mm (3") diameter. Please verify these details against your engine and existing pump.

Q: Is this kit compatible with Japanese-built Yanmar GM engines?

A: No, this kit is designed exclusively for the European-built models (-YEU). The pumps on Japanese-built models are different. Please double-check your engine's model and serial number before ordering.

Q: What are common signs that my sea water pump needs a rebuild?

A: Common signs of failure include the engine overheating at idle or low speeds, visible water leaks from the pump itself (weep holes), reduced water flow from the exhaust, or a damaged or brittle impeller found during routine inspection. It is recommended to inspect your impeller annually and replace it as a preventative measure.

Q: OEM vs. Aftermarket?

A: This listing is an aftermarket replacement part (not an OEM component). We build to OEM specifications using comparable-grade materials. Production is done in an ISO9002-certified facility, and each batch is inspected for consistent performance.

Q: How fast do you ship and how much does it cost?

A: We offer fast global shipping—typically 5–15 days worldwide—and standard shipping is free. Expedited options are available at checkout depending on your location.

Q: What is your warranty and return policy?

A: This product includes a 1-year warranty against manufacturing defects under normal use. If something goes wrong, contact our support team with your order details. Returns are accepted within our standard return window (unused & in original condition); please see our policy page or reach out for instructions.

Important Notes

• Verify that the product images and specifications match your original part. If discrepancies exist—even if your model is listed—do not proceed with the purchase.
• This product is an aftermarket replacement part and is not an OEM component.
• Professional installation is recommended to ensure safety and optimal performance.

Why Choose JLM MARINE?

• Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
• Fast Global Shipping: Free delivery worldwide in 5–15 days.
• Direct from Manufacturer: Competitive pricing without compromising quality.