1990 Yamaha 4LD Outboards. The procedures in this manual are organized in a step-by-step format. The information has been compiled to provide the mechanicwith an easy to read, handy reference that contains comprehensive explenation of all disassembly, repair,assembly and inspection operations. Each chapter provides exploded diagrams before each disassembly section for ease in identifying the correct disassembly and assembly procedures. The manual is completly bookmarked and searchable. It covers everything about the motor. Don‘t pay $70 or more for the same info from the dealer!