This manual covers the 3JH2-(B)E, 3JH2-T(B)E, 3JH25A, and 3JH30A marine diesel engines. Engineered for demanding marine applications, these diesel engines, with turbocharged options available for specific models, represent a commitment to robust performance and reliability. The dedication to quality ensures these units are built to withstand the rigorous conditions encountered in marine environments, providing dependable power for a wide range of vessels. This comprehensive workshop and full service repair manual provides essential information for the maintenance and repair of your marine diesel engine. It includes hundreds of pages of detailed step-by-step instructions, clear photos, diagrams, and exploded views to guide owners and technicians through every procedure. The manual is designed to facilitate efficient troubleshooting, accurate technical reference, and proper maintenance, ensuring the longevity and optimal performance of your engine.