This manual covers the YANMAR BY Series (4BY2 and 6BY2) marine diesel engines, designed for reliable marine propulsion. The 4BY2 model features a 4-cylinder diesel engine with a displacement of 2.043 L, while the 6BY2 model is equipped with a 6-cylinder diesel engine displacing 3.065 L. Both are liquid-cooled, internal combustion engines that utilize diesel fuel, representing YANMAR Co., Ltd.'s commitment to engineering quality and performance in marine applications.

This comprehensive Full Service Repair Manual in English provides essential information for the maintenance and repair of your YANMAR marine engine. It details critical procedures, troubleshooting guides, technical specifications, and safety guidelines. Owners, mechanics, and technicians will find the necessary data to ensure the optimal performance, longevity, and reliability of their 4BY2 and 6BY2 series engines, including guidance on recommended service intervals, oil types, inspection schedules, and oil capacities specific to each model.