This Service Repair Workshop Manual provides comprehensive information for the YANMAR 1GM10 and 2GM20 Marine Diesel Engines. Engineered for reliability and performance, these diesel engines are designed for demanding marine applications. Their robust construction and efficient operation make them a trusted choice for boat owners and operators seeking dependable power on the water. This manual covers essential details to ensure optimal functionality and longevity of your YANMAR marine diesel engine. The purpose of this manual is to serve as a definitive guide for the repair, servicing, and troubleshooting of the YANMAR 1GM10 and 2GM20 models. It includes step-by-step instructions, detailed photos, and exploded diagrams to facilitate understanding and execution of maintenance procedures. This resource is invaluable for owners, mechanics, and technicians aiming to maintain the peak performance and operational integrity of these marine diesel engines.