This service repair manual covers the Yamaha 90A Outboard, an outboard engine designed for marine applications. While specific production years are not detailed, this manual encompasses all styles of the model. The 90A Outboard is engineered for reliability and performance, featuring a robust 90 HP power output. Its design focuses on efficient operation, with key systems including the fuel system, power unit, and electrical system thoroughly addressed. This comprehensive manual provides essential information for maintaining and repairing your Yamaha 90A Outboard. It details periodic checks, standard maintenance procedures, and specific repair instructions for components such as brakes, suspension, and engine running issues. Included are wiring diagrams and troubleshooting guidance to help diagnose and resolve problems. The manual's step-by-step instructions, supported by numerous photos and illustrations, are designed for clarity, enabling owners and technicians to keep the engine in optimal condition.