JH Series 4JH4 (54HP/39.6kW)
Wisper quiet, smooth running at all speeds and with extremely low vibrations, it produces 25% more torque from just 10% additional displacement compared to the model it replaces but precisely the same size.

Dedicated to boating and with the smallest dimension in it's class, the 4JH4 matched several transmission options, including the heavy duty SD40 saildrive with it's patented dual-seal diaphragm and audible water sensor.

Lightweight:
Compact design iron block and head feature close spaced cylinders to save space and weight. Extensive use of aluminum alloys in oil pan, covers, and many parts make for good weight savings.

User Friendly:
Sophisticated engine mounts, a range of ultra-smooth transmissions, micro-precision fuel system components, close attention to bearing tolerances and accurate balance of moving parts make for low noise, low vibration, low emission, low downtime and an easy-to live with engine.

Clean:
Inlet swirl design improves fuel-air mix, extra high pressure fuel injection system with micron-precision injectors and close attention to coolant flow minimizes hot and cool spots – these are just some of the ways Yanmar improves combustion efficiency. Exhaust gas emissions on all 5 engines clear the strict European BSO regulations. Efficient: Diesels are synonymous with fuel economy. Being a Yanmar also means long years of experience in building some of the world’s most efficient diesels. Extensive input from our large and extremely modern research facilities have been incorporated into every new Yanmar engine.

Reliable:
Long, trouble-free, engine life is a common reason for choosing Yanmar. Worldwide parts backup and quick response times make for minimum downtime. These engines are again and again the favored choice of bluewater yachtsmen and boat owners the world over.

28.7–92kW (39–125HP)
Three and four-cylinder direct injection diesels with heat exchanger cooling. Choices of natural aspiration, turbocharged and turbo/aftercooler models, with straight drive or angle drive transmissions. Smaller horsepower models are also offered with Saildrive units.