This manual covers the Kohler PCH680, an internal combustion engine designed for repair, maintenance, rebuild, refurbish, and restoration. The PCH680 is engineered for reliability and performance, making it a crucial component in various applications where robust power is required. Understanding its intricate systems is key to ensuring its longevity and optimal operation. This comprehensive English-language service manual provides detailed instructions for repair, maintenance, rebuild, refurbish, and restore procedures, along with diagnostics and electrical service. It includes essential wiring diagrams and service schedules, presented with numbered steps, detailed sub-steps, and bold figure numbers for clarity. Safety information, including notes, cautions, and warnings, is integrated throughout. Detailed illustrations, drawings, photos, and enlarged inset details aid in understanding complex procedures. The manual is intended for professional technicians and do-it-yourself mechanics, offering the necessary information to maintain and repair the Kohler PCH680 engine effectively.