Model Variant:
3YM20 marine diesel engine
Production Years Covered:
2000s–2010s production range; specific years not stated in the manual
Engine Type:
Naturally aspirated, 3-cylinder marine diesel
Platform:
Yanmar YM series marine diesel
Target Audience:
Boat owners, marine mechanics, and technicians servicing Yanmar marine diesel engines
Application:
Auxiliary propulsion and auxiliary power for sailboats and small motorboats
Competitive Advantage:
Compact, lightweight, reliable naturally aspirated design with widely available parts support
Key Features:
20 HP output, indirect fresh water cooling, forced lubrication, robust marine-grade construction
General Information:
Specifications, identification, and service data
Engine Mechanical:
Cylinder head, block, piston, and crankshaft service
Engine Electrical:
Starting and charging systems, sensors, and wiring
Fuel System:
Fuel injection pump, injectors, and fuel lines
Cooling System:
Fresh water and raw water cooling circuit service
Lubrication System:
Forced lubrication circuit, oil pump, and oil filter
Emission Control:
Emission-related components and adjustments
Troubleshooting:
Diagnostic procedures for common engine faults
Step-by-Step Repair:
Detailed disassembly, inspection, and reassembly procedures
Wiring Diagrams:
Electrical schematics for engine circuits
Adjustments:
Valve clearance, injection timing, and belt adjustments
Specifications:
Torque values, clearances, and service limits
Parts Information:
Component identification and replacement guidance
Technical Depth:
Factory-level service and repair detail
File Format:
PDF (searchable, bookmarked, zoomable)
Compatibility:
Windows, macOS, Linux, iOS, and Android — any device with a PDF reader
Requirements:
A PDF reader application (e.g. Adobe Acrobat Reader, free)
Searchability:
Fully text searchable for fast lookup of any topic
Print Quality:
High-resolution digital pages, printable at full clarity
Binding Type:
N/A — digital download, no physical binding
Paper Type:
N/A — digital download, no physical paper
Configuration:
Naturally aspirated, 3-cylinder diesel
Displacement:
0.57 L (570 cc)
Rated Power:
20 HP (14.7 kW) at 3200 RPM
Cooling:
Indirect fresh water cooling
Lubrication:
Forced lubrication system
Fuel System:
Indirect injection diesel fuel system
Engine Options Range:
No alternative ratings listed for this model
Wheelbase:
N/A - not applicable to a marine engine
Length:
N/A - overall engine dimensions not specified in the source description
Width:
N/A - not specified in the source description
Height:
N/A - not specified in the source description
Curb Weight:
N/A - dry engine weight not specified in the source description
Infotainment:
N/A - not applicable to a marine engine
Driver Assistance:
N/A - not applicable to a marine engine
Instrumentation Support:
Compatible with tachometer, hour meter, and warning lamp panel
Charging:
Alternator charging system for vessel batteries
Service Intervals:
Routine oil, filter, impeller, and fuel filter service; follow the manual schedule for this model
Engine Oil:
Marine diesel engine oil meeting the manufacturer viscosity recommendation
Coolant:
Fresh water coolant mixture per manufacturer specification
Common Wear Items:
Impeller, fuel and oil filters, belts, and zinc anodes
Known Issues:
Cooling and fuel system faults common to marine diesel installations
