This textbook (©2023) is designed to provide students, do-it-yourselfers, and aspiring technicians with practical up-to-date information about small gas engine construction, operation, lubrication, maintenance, troubleshooting, service, rebuilding, and repair. The text is written in clear, non-technical language, and provides detailed information about one-, two-, and three- cylinder, two-cycle, and four-cycle gasoline engines.