This manual covers the YANMAR 4LHA Series Marine Diesel Engine, a robust and reliable four-cylinder water-cooled engine designed for marine applications. Engineered for performance and durability, the 4LHA series is built to meet the demanding requirements of maritime operations. Its advanced fuel injection system and efficient design ensure optimal power delivery and operational longevity, making it a trusted choice for boat owners and operators. This comprehensive Service Repair Manual in English provides detailed information for maintaining and repairing your YANMAR 4LHA Series engine. It includes essential sections on basic engine operation, fuel injection, intake and exhaust systems, lubrication, cooling, and the reduction and reversing gear. With service and repair procedures, disassembly and assembly instructions, wiring and electrical diagrams, and photo illustrations, this manual is an indispensable resource for ensuring the continued performance and reliability of your marine diesel engine.