This operation manual provides comprehensive information for the Deutz 914 series engines, including the F3L914, F4L914, F5L914, F6L914, BF3L914, BF4L914, BF6L914, and BF6L914 C models. Designed for reliable performance and efficiency, these engines represent advanced engineering for various applications. This factory manual details their construction, operational principles, and essential care to ensure optimal functionality and longevity. The purpose of this manual is to serve as a definitive guide for owners, operators, and service technicians. It covers all aspects of engine management, from initial operation and fluid requirements to detailed routine maintenance, in-depth service procedures, and troubleshooting guidance for common faults. Included are critical technical specifications and recommendations for engine preservation, empowering users to maintain their Deutz 914 engines effectively and safely.