Yanmar 3GMF Marine Diesel Engine

The Yanmar 3GMF is a compact, fuel-efficient, and highly reliable inboard marine diesel engine delivering approximately 20–27 HP (depending on configuration and rating). Designed for auxiliary propulsion on sailboats and small cruising vessels, the 3GMF is part of Yanmar renowned GM series, known worldwide for durability, smooth operation, and long service life.

Engine Design & Construction

The 3GMF features a 3-cylinder, 4-stroke diesel configuration with direct mechanical fuel injection, providing responsive throttle control and consistent power output. Its robust cast-iron engine block and precision-engineered components are built to withstand continuous operation in demanding marine environments.

A freshwater cooling system with heat exchanger protects internal components from corrosion while maintaining stable operating temperatures. The compact engine footprint allows installation in tight engine rooms, making it ideal for repower projects.

Performance & Efficiency

Delivering dependable power for cruising, maneuvering, and docking, the Yanmar 3GMF offers strong low-RPM torque and smooth acceleration. The 3-cylinder layout minimizes vibration and noise, improving onboard comfort during long passages.

The efficient fuel injection system ensures excellent fuel economy, reducing operating costs while maintaining consistent performance.

Marine Integration

The Yanmar 3GMF is designed for shaft-drive inboard installations and is compatible with Yanmar marine gearboxes. Its predictable power delivery and precise throttle response make close-quarters handling easier in marinas and harbors.

Ease of Maintenance & Reliability

Yanmar engines are known for serviceability, and the 3GMF is no exception. Easily accessible service points simplify routine maintenance, while the engine’s mechanical design ensures long-term reliability. With Yanmar global service network, parts availability and technical support are widely accessible.

Ideal Applications

The Yanmar 3GMF Marine Diesel Engine is ideal for:

• Sailboats and auxiliary propulsion systems

• Small to mid-size cruising yachts

• Coastal and offshore sailing

• Repower and replacement projects

Key Advantages

• Proven Yanmar marine diesel reliability

• Compact and lightweight design

• Fuel-efficient mechanical injection system

• Freshwater cooling with heat exchanger

• Smooth, low-vibration operation

• Easy maintenance and long service life

Technical Specifications

General

• Model: Yanmar 3GMF

• Engine Type: 4-stroke, vertical, water-cooled marine diesel

• Fuel System: Direct mechanical fuel injection

• Aspiration: Naturally aspirated

• Number of Cylinders: 3 inline

Displacement & Combustion

• Displacement: Approx. 1.00 liter

• Bore × Stroke: Approx. 75 mm × 76 mm

• Combustion System: Direct injection diesel

Performance

• Rated Power: Approx. 20–27 HP @ 3,400 RPM (depending on rating/version)

• Maximum Speed: Approx. 3,400 RPM

• Torque Characteristics: Strong low- and mid-range torque

• Fuel Consumption: Economical, varies with load and propeller selection

Cooling & Lubrication

• Cooling System: Freshwater cooling with heat exchanger

• Lubrication System: Forced lubrication with trochoid oil pump

• Engine Oil Capacity: Approx. 3.0 liters

• Recommended Oil Type: Marine-grade diesel engine oil

Electrical System

• Starting System: 12 V electric start

• Alternator: 12 V marine alternator

Dimensions & Weight

• Overall Dimensions (L × W × H): Approx. 670 × 500 × 560 mm

• Dry Weight: Approx. 120–130 kg (engine only, excluding gearbox)

Drive & Installation

• Rotation (Crankshaft): Counter-clockwise (viewed from flywheel end)

• Drive Type: Inboard shaft drive

• Compatible Gearbox: Yanmar marine transmission

• Mounting: Flexible marine engine mounts

Service & Adjustment

• Valve Clearance (Cold): Intake: 0.20 mm / Exhaust: 0.25 mm

• Firing Order: 1 – 2 – 3

• Maintenance Access: Easy access to filters, belts, and routine service components