This service manual covers the Yamaha EF3300, EF4000, and EF4000D portable generators. These generators are powered by reliable 4-stroke, OHC, forced air-cooled gasoline engines with displacements of approximately 171 cc for the EF3300 and 208 cc for the EF4000 and EF4000D models. The EF3300 offers a rated output of 3.3 kVA, while the EF4000 and EF4000D provide 4.0 kVA, with the EF4000D featuring inverter technology. Designed for dependable power generation, these units utilize a direct drive transmission system and are built with quality engineering for consistent performance.

This English-language service manual provides comprehensive information essential for the maintenance and repair of your Yamaha generator. It details critical procedures, technical specifications, and troubleshooting guidance for the EF3300, EF4000, and EF4000D models. Key areas covered include engine specifications, maintenance schedules with recommended oil types and capacities, and initial and regular service intervals. This manual is an indispensable resource for owners, technicians, and mechanics seeking to ensure the optimal performance and longevity of their Yamaha generator.