This manual covers the Yanmar Mase Marine Generators IS 5.0 and IS 6.0 series. These diesel-powered generators are engineered for reliable performance in marine applications, providing essential electrical power. While specific production years are not detailed, this workshop service repair manual encompasses a range of model years for these generator sets, which typically feature raw water cooling and deliver 5.0 kW or 6.0 kW of power output depending on the specific model. The purpose of this comprehensive English-language workshop service repair manual is to provide detailed information for the maintenance and repair of the Yanmar Mase Marine Generators. It includes complete service and repair procedures, technical specifications, and guidance on electrical system controls and output. This manual is an indispensable resource for owners, mechanics, and technicians to ensure the optimal performance, longevity, and safe operation of these marine generator sets.