Marine Maintenance Solution for Yanmar Engines: JPR-YM04JHA Pump

December 26, 2025

For anyone focused on reliable marine maintenance, few systems are as critical as engine cooling. The JPR-YM04JHA JMP Marine Yanmar Replacement Engine Cooling Raw Water / Seawater Pump is designed to keep your Yanmar engine running cool, efficient, and protected in demanding marine environments. Built for durability and precision, this pump is a dependable solution for both routine marine maintenance and full pump replacement on Yanmar 3JH and 4JH series engines.

Whether you’re performing scheduled service or addressing a worn OEM pump, the JPR-YM04JHA delivers a true plug-and-play replacement. It replaces genuine Yanmar pump part number 129670-42513 (and supersedes 129670-42500, -42501, -42510, -42511, and -42512), as well as Johnson pump part numbers 10-13328-02 and 10-13328-04. With the drive gear included, installation is straightforward, reducing downtime and keeping marine maintenance on schedule.

Built for Marine Performance & Long-Term Durability

The JPR-YM04JHA is engineered specifically for harsh marine conditions and continuous operation:

• A strong bronze body (not brass) provides superior corrosion resistance and structural strength in saltwater environments.

• The 3X Series non-magnetic marine-grade shaft delivers long-term durability and reliable performance under load.

• A high-performance flexible impeller (JMP 7100-01K) ensures consistent raw water flow and effective engine cooling.

• O-ring end cover packing improves sealing, helping prevent leaks and pressure loss over time.

• High volume flow capacity supports stable operating temperatures, even during extended runs.

At approximately 5.5 lbs (2.50 kg), this pump balances compact design with heavy-duty construction—ideal for professional marine maintenance and DIY servicing alike.

Optimized for Preventive Marine Maintenance

Preventive marine maintenance is key to avoiding overheating, corrosion, and unexpected engine failure. The JPR-YM04JHA supports a proactive service strategy with readily available maintenance components, including the Major Service Kit JSK0130 and Minor Service Kit JSM0130 (sold separately). Because the pump is internally compatible with genuine Yanmar units, it integrates seamlessly into existing maintenance programs while offering improved durability and performance.

Reliable Cooling for Yanmar 3JH & 4JH Engines

Designed for Yanmar engines with a 90-degree elbow, the JPR-YM04JHA supports a wide range of models, including 3JH3, 4JH3, and 4JH4 series engines such as 4JH3-TE, 4JH3-DTE, 3JH3E, and 4JH4-HTE1. From commercial vessels to cruising sailboats, this pump delivers dependable cooling performance that enhances overall engine reliability.

As part of the JMP Marine lineup, the JPR-YM04JHA ensures your marine maintenance efforts result in longer engine life, reduced downtime, and confidence every time you leave the dock.

As we like to say: JMP MARINE… “THE ONLY ONE.”