Mercury Marine diesel engine update

RCD II compliant, this reworked engine now features a biofuel capability. Mercury Marine has launched the latest incarnation of its Mercury Diesel 4.2L marine engine. Introduced at the Düsseldorf Boat Show this January in both 270hp and 320hp versions, this engine is designed to run on regular diesel fuel or HVO biofuel. 

HVO (Hydrotreated Vegetable Oil) is an ecological and sustainable synthetic diesel produced mainly from renewable sources such as plant oils and vegetable fats. By running on HVO, the engine achieves a reduction in particulate matter (PM), nitrogen oxides (NOx), and CO₂ emissions. Additionally, with a low gelling point of -32°C, it is well suited for cold-weather operation. Fully compliant with the RCD II emissions standard, it is available for sale in the European Union and in all markets that recognise RCD II certification. 

Like all modern turbocharged diesel engines, it utilises common-rail fuel injection and an intercooler. With an engine-only weight of 460kg, it is claimed to be 15% lighter than its closest competitor. For repowering applications, it may also be rigged with previous-generation SmartCraft 2.2 systems. 

To power onboard electronics and appliances, the engine features an alternator delivering 110 amps of peak charging power. Maintenance is made easier thanks to top-mounted fluid reservoirs, a self-draining oil filter, and an easily accessible oil dipstick. 

This engine range is fully compatible with Mercury Marine’s Next Gen DTS control technology and JPS Precision Joystick control. It is available in both sterndrive and inboard configurations. The Mercury Diesel 4.2L is offered with MerCruiser Bravo I X/XR, Bravo II X/XR, and Bravo III X/XR sterndrives or, for inboard installations, with ZF68 A, ZF68 IV, and ZF68 transmissions. 

A notable point is that Mercury Marine will continue to offer versions of this engine with EPA Tier 2 and IMO II emissions certification at 270hp, 320hp, and 350hp outputs for markets accepting Tier 2 certification. However, the RCD II-compliant engine is not EPA Tier 3 certified and is therefore not available for sale in the USA or Canada. The RCD II-compliant engine will be available for shipment beginning in March 2025. 

Mercury Diesel 4.2L (RCD II) – 320 Horsepower 

• Peak Engine Torque: 703 Nm (519 lb ft) at 2600 RPM
• Wide-Open Throttle (WOT) Fuel Consumption: 71.9 l/hr (19.0 gal/hr)

Mercury Diesel 4.2L (RCD II) – 270 Horsepower 

• Peak Engine Torque: 603 Nm (444 lb ft) at 2600 RPM
• WOT Fuel Consumption: 60.6 l/hr (16.0 gal/hr)

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