This service repair manual covers the EF3300, EF4000, and EF4000D generators. These generators are designed to provide reliable power for various applications, featuring gasoline 4-stroke engines that deliver rated power outputs of 3300 Watts for the EF3300 and 4000 Watts for the EF4000 and EF4000D models. The engineering behind these units prioritizes dependable operation and extended service life, aiming to reduce the need for extensive repairs and ensure consistent performance. This comprehensive manual is designed to assist owners, mechanics, and technicians in maintaining and repairing these generators. It provides detailed information on periodic maintenance, with a specific focus on the emission control system, to ensure reliable operation and prolong the unit's service life. The manual also includes diagnostic methods for troubleshooting, enabling efficient identification and resolution of potential issues. This English language guide is presented in a fully printable format.