Enhance Your Marine Maintenance Routine with the JPR-YM04JHB JMP Marine Yanmar Cooling Pump

December 22, 2025

For anyone serious about marine maintenance, keeping your engine’s cooling system in peak condition is essential. The JPR-YM04JHB JMP Marine Yanmar Replacement Engine Cooling Raw Water / Seawater Pump is designed to make that job easier, more reliable, and more efficient. Engineered with precision and durability, this replacement pump ensures optimal cooling for Yanmar 3JH and 4JH series engines — trusted powerhouses in commercial, leisure, and offshore applications.

Whether you’re performing scheduled marine maintenance or replacing a worn OEM unit, the JPR-YM04JHB offers the perfect plug-and-play solution. It directly replaces Yanmar part numbers 129271-42502, 129271-42500, 129271-42501, as well as Johnson pumps 10-13328-01 and 10-13328-03, while delivering enhanced longevity and flow performance for demanding marine conditions.

Built for Marine Performance & Durability

Every aspect of the JPR-YM04JHB is built for real-world reliability:

• Heavy-duty bronze body resists corrosion and wear, outperforming standard brass designs in saltwater environments.

• 3X Series non-magnetic marine-grade shaft ensures long-term durability and stability under continuous operation.

• High-performance flexible impeller (JMP 7100-01K) delivers consistent water flow and improved cooling efficiency.

• O-ring end cover packing and included drive gear with mounting gasket make installation fast, secure, and reliable.

• High volume flow capacity keeps your engine cool even under heavy load conditions.

Weighing 5.5 lbs (2.50 kg), this pump combines compact size with heavy-duty construction, giving marine maintenance professionals confidence in every service.

Optimized for Preventive Marine Maintenance

Regular inspection and marine maintenance of your cooling system are key to preventing overheating, corrosion, and mechanical failure. The JPR-YM04JHB supports this proactive approach, making routine service simple with available Major Service Kit JSK0130 and Minor Service Kit JSM0130 (sold separately).

Because it’s internally compatible with genuine Yanmar pumps, it integrates seamlessly into existing setups while improving longevity and cooling performance. The included drive gear and mounting gasket ensure proper alignment, a secure seal, and minimal downtime.

Dependable Performance for Demanding Applications

From commercial vessels to private yachts, the JPR-YM04JHB provides consistent cooling flow across Yanmar 3JH and 4JH series engines — including models 3JH4E, 3JH5E, 4JH4E, 4JH4AE, 4JH57, and 4JH110. This precision-engineered pump is part of JMP Marine’s legacy of innovation, ensuring that your marine maintenance efforts lead to better engine performance, reliability, and longer engine life.

JMP MARINE… “THE ONLY ONE.”