This manual covers the Yamaha 90A Outboard motor, a robust and reliable piece of marine engineering designed for a variety of watercraft. While specific production years are not detailed, the 90A model is engineered for performance and durability, making it a suitable choice for both recreational and professional use. Its design prioritizes efficiency and longevity, ensuring consistent operation across different conditions. The purpose of this comprehensive workshop service repair manual is to provide detailed guidance for the maintenance and repair of the Yamaha 90A Outboard. It includes step-by-step instructions, hundreds of photos and illustrations, and covers all aspects from periodic checks and adjustments to complete disassembly. This resource is invaluable for do-it-yourself enthusiasts and experienced mechanics alike, offering troubleshooting advice, electrical system diagnosis, and detailed technical specifications, including wiring diagrams, to ensure the optimal performance and longevity of your outboard motor.