The Yanmar YM Series delivers compact inboard propulsion for sailing yachts, cruising boats and other small marine craft. These naturally aspirated, water-cooled diesel engines combine mechanical operation with a lightweight installation footprint, making them suitable for new builds and for owners replacing an older sailboat engine.
Three output choices allow the engine to be matched more closely to the vessel. The two-cylinder Yanmar 2YM15 produces 14 mhp (10 kW), while the three-cylinder Yanmar 3YM20 provides 21 mhp (15.3 kW). At the top of the range, the Yanmar 3YM30AE develops 29.1 mhp (21.3 kW), offering additional propulsion capacity for larger or more heavily equipped sailing boats.
These Yanmar sailboat engines use indirect fuel injection, natural aspiration and mechanical controls. The 2YM15 and 3YM20 reach their rated output at 3,600 rpm, whereas the larger 3YM30AE is rated at 3,200 rpm. A Yanmar B20 panel, freshwater-cooling expansion tank, flexible engine mounts, electric stop solenoid and exhaust mixing elbow are included in the standard package, subject to the selected configuration and market.
A Yanmar YM marine diesel engine can be configured with a compatible Kanzaki shaft-drive transmission or an SD25 saildrive. Final selection should consider more than horsepower: the vessel’s displacement, hull type, propeller demand, reduction ratio, engine-bed dimensions, exhaust routing and cooling-water arrangement must all be reviewed. Repower projects should also verify coupling dimensions, shaft alignment, control-cable compatibility and access for routine maintenance.
Before ordering, confirm whether the required engine is the 2YM15, 3YM20 or 3YM30AE, together with the proposed gearbox or saildrive, reduction ratio, control panel and supplied accessories. A written quotation should identify the exact Yanmar YM engine package, rated output, transmission configuration, optional equipment, warranty terms, production lead time, packing method and delivery conditions.
