This manual covers the Vanguard Twin Cylinder OHV Engine, a robust and reliable power unit designed for a wide range of applications. Featuring Overhead Valve (OHV) technology and air cooling, this engine is engineered for efficient operation and durability. Its twin-cylinder configuration provides ample power and smooth performance, making it suitable for demanding tasks where consistent output is essential. The engine family codes include 290000-350000, 351400, 380400, 351700, and 380700, indicating its versatility across various equipment types. This comprehensive Service Repair Manual provides detailed guidance for the maintenance, repair, and troubleshooting of your Vanguard Twin Cylinder OHV Engine. It covers essential procedures such as safety precautions, scheduled maintenance, adjustments, engine disassembly and assembly, and specific component repairs including the fuel system, lubrication system, cylinder heads, valves, and starters. With clear instructions and technical specifications, this manual is an indispensable resource for owners, mechanics, and technicians seeking to ensure the optimal performance and longevity of their engine.