This workshop service repair manual covers JLO engines, including single-cylinder models such as the L-99, L-230, L-295, L-227, R-295, L297, L-300, L-340, and R-340, as well as twin-cylinder models including the LR-340/2, LR-399/2, LR-440/2, and LB-600/2. These engines are known for their robust engineering and reliability, making them suitable for a variety of applications. This manual is designed to provide comprehensive information for maintaining and repairing these JLO engines. The purpose of this English-language manual is to offer detailed guidance for owners and technicians. It covers essential maintenance procedures, troubleshooting common issues, and provides technical specifications. Key topics include engine fundamentals, operating instructions, carburetor and ignition system service, disassembly and assembly, timing, wiring diagrams, and dimensional data. The manual's quick search functionality and detailed troubleshooting section are intended to facilitate efficient repair and upkeep, ensuring the longevity and optimal performance of your JLO engine.