The Yanmar 3YM20 Marine Diesel Engine is a powerful and fuel-efficient 3-cylinder, 4-stroke marine engine designed for small to medium-sized boats. Delivering 21hp at 3600 rpm, this compact engine is known for its smooth, quiet operation and reliability in tough marine environments. Designed with Yanmar’s advanced engineering, the 3YM20 provides exceptional performance for sailboats, yachts, and smaller commercial vessels.
The engine is equipped with direct fuel injection for improved fuel efficiency, reduced emissions, and enhanced power output. Additionally, the freshwater cooling system with heat exchanger helps maintain optimal operating temperatures and prevents internal corrosion, increasing the engine’s lifespan. The 3YM20 is compliant with global emission regulations, making it a greener choice for marine applications.
Technical Specifications:
- Engine Model: 3YM20
- Engine Type: 3-cylinder, 4-stroke, vertical water-cooled diesel engine
- Displacement: 0.854 litres (854 cc)
- Bore x Stroke: 70 mm x 74 mm
- Power Output: 21hp (15.3 kW) at 3600 rpm
- Compression Ratio: 23.5:1
- Cooling System: Freshwater cooling with heat exchanger
- Fuel Injection System: Direct injection
- Alternator Output: 12V – 125A
- Lubrication System: Forced lubrication by trochoid pump
- Oil Capacity: 3.5 litres
- Starting System: Electric start
- Direction of Rotation: Counterclockwise (viewed from flywheel)
- Weight: Approx. 119 kg
- Gearbox Options: KM2P, KM35A (mechanical or hydraulic)
- Reduction Ratios: 2.21:1 or 3.22:1
- Exhaust System: Water-cooled, with wet exhaust manifold
- Fuel Consumption: Approx. 1.8 litres/hour at cruising speed
- Emission Compliance: Meets Tier 2 and EU RCD emission standards
Key Features:
- Fuel Efficiency: Direct injection system optimises fuel consumption while reducing emissions.
- Durable Construction: Built for the marine environment with corrosion-resistant materials and an efficient cooling system.
- Compact Design: Ideal for smaller boats and tight engine compartments.
- Low Noise and Vibration: Designed for smoother, quieter operation, improving the comfort of your boating experience.
- Freshwater Cooling System: Increases engine longevity by preventing internal corrosion and maintaining stable temperatures.
- Compliant with Global Emissions Standards: Environmentally friendly engine, meeting Tier 2 and EU RCD regulations.
Yanmar is a world-renowned manufacturer of high-quality marine engines, offering a range of compact, durable, and fuel-efficient diesel engines for boats of all sizes. The Yanmar 3YM20 exemplifies Yanmar’s dedication to reliability and advanced engineering, providing smooth, quiet operation and environmentally-friendly performance.
Yanmar 3YM20 engine is available with three transmission options for marine applications. The KM2P-1 is a mechanical marine gear that provides smooth operation with a hydraulic clutch and selectable gear ratios. The SD25 SailDrive is a compact, low-vibration system that integrates directly with specific Yanmar engines, offering enhanced performance for sailboats. Additionally, bobtail engines are available, which are complete engine replacements for both stern drive and inboard applications, including essential systems such as fuel, electrical, cooling, and exhaust.
