Main Engine 4-Stroke · Main Engines (4-Stroke)
This auxiliary engine operates on a vertical single-acting inline configuration, employing a 4-stroke cycle with direct injection and compressed air motor starting, making it well-suited for marine applications. The Yanmar 5N21L is part of the 6EY26 engine family and features five cylinders with a bore of 210 mm and a stroke of 320 mm, offering a maximum continuous rating (MCR) of 1250 kW at 900 RPM. Certified to IMO Tier II standards, it supports both Marine Diesel Oil (MDO) and Heavy Fuel Oil (HFO) with a preheating system for HFO operation. Notable for its widespread use on bulk carriers and tankers, the engine benefits from a robust service network in Asia. Common issues include turbocharger oil leakage leading to intercooler clogging and reduced boost pressure, fuel injection system carbon deposits and water contamination causing injector blockages, galvanic corrosion in the seawater cooling system, crankshaft journal ovality and cracks, and oil sludge accumulation affecting lubrication efficiency.
Every value below comes from the manufacturer datasheet or class-society record on file for this model.
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