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Yanmar Marine Diesel 3JH4:

Yanmar marine 3JH4 marine diesel engine

40-hp - with 25% more torque than the motor it replaces

Yanmar Marine's 3JH4 engine is a compact, naturally aspirated, environmentally-friendly marine diesel engine boasting both inboard and sail drive optional transmission packages. Rated a 40 hp @ 3000 rpm, the 3JH4 builds 25% more torque with only a 9% increase in its displacement.

Its greater output does not extract a penalty in noise control. Fitted with a new intake silencer design, plus the low-vibration TNV platform and lower operating rpm, this latest offering from Yanmar is a full 5 dB quieter than previous models. Naturally, it runs cleaner and produces less smoke. Suffice to say it complies with EPA Tier 2 regulations.

Boat builders and repower mechanics will rub their hands together in glee when they learn the new 3JH4 fits within the same footprint as the company’s previous generation of 3-cylinder models. This engine is also user friendly. Its gear-driven seawater pump is mounted in the front of the engine for easy maintenance. The newly designed V-pulley drive belt ensures long belt life. An electric-stop solenoid is a standard item.

The new, optional compact control panel features an hour meter. The theme of more power in a smaller footprint continues with Yanmar´s third introduction for the 2004 boating season. Its revised 4JH3 diesel boasts 25 percent more torque than last year’s model. Obviously this ideal power to weight ratio make it a serious contender for repowering. The engine, rated at 54 hp @ 3000 rpm, had its displacement bumped by 10%. True to the old saying, there is no substitute for cubic inches. But the payoff here is more cubes and more power, but without an increase in size.

In addition to the extra horsepower, the new Yanmar runs significantly quieter. Once again the soft voice is due to a larger silencer, low-vibration engine mounts plus a lower operating rpm. Want hard numbers? Engine noise is effectively reduced by a full five dB. Heart and soul of the Yanmar is its completely redesigned cylinder block bolstered by a new combustion system, including a swirling pre-combustion chamber and direct injection.