This Service and Repair Manual covers Yamaha Marine Outboard Motors, specifically the F80A, F100A, F80X, and F100X models. Yamaha is renowned for its commitment to engineering excellence, producing reliable and high-performance marine propulsion systems. These outboard motors are designed for a wide range of marine applications, offering robust performance and durability for both recreational and professional use. This manual provides comprehensive information to ensure these engines operate at their peak efficiency and longevity. The purpose of this manual is to serve as a definitive guide for the maintenance, servicing, and repair of your Yamaha outboard motor. It includes detailed procedures for complete tear-down and rebuilds, comprehensive troubleshooting guides, and essential technical maintenance instructions. You will find information on periodic inspections, adjustments, torque specifications, and part diagrams. Electrical and hydraulic diagrams are also included, along with detailed illustrations, exploded diagrams, drawings, and photos to assist owners, mechanics, and technicians in understanding and performing all necessary tasks.