This manual covers Yamaha 4-Stroke Outboard models manufactured between 1999 and 2005, offering a range of horsepower options from 75 HP to 100 HP. These engines are engineered for reliable performance and efficiency, featuring a 4-stroke configuration that ensures smooth operation and reduced emissions. Their robust construction and advanced design make them suitable for a variety of marine applications, providing dependable power for recreational and professional use alike. This comprehensive guide serves as both a repair manual and an owner's guide, detailing essential information for maintaining and servicing your Yamaha outboard. It includes in-depth coverage of general information, routine maintenance procedures, engine specifications, and advanced troubleshooting techniques. The manual also provides guidance on the fuel system, lubrication, cooling system, electrical system, and transmission, equipping owners and technicians with the knowledge necessary to keep the engine in optimal condition and ensure its longevity.