This manual covers the Yamaha 60, 70, 75, and 90 hp outboard motors manufactured in 1999. These gasoline-powered outboard motors are engineered for reliable performance on the water. This service and repair manual provides comprehensive information designed to assist users in understanding and maintaining these robust marine engines, ensuring their continued operational efficiency. The purpose of this English-language service and repair manual is to offer detailed guidance for the maintenance and repair of the specified Yamaha outboard motors. It includes essential sections such as general information, specifications, periodic inspection and adjustment, fuel system, power unit, lower unit, bracket unit, electrical unit, and troubleshooting. This manual is an indispensable resource for owners, technicians, and mechanics seeking to perform accurate diagnostics and repairs.