This Service & Maintenance Manual covers Tecumseh 4-Cycle L-Head Engines, ranging from 3 to 11 horsepower. These engines are characterized by their single-cylinder, air-cooled design, typically featuring electronic ignition and float bowl carburetors. They utilize either splash or forced lubrication systems and are engineered for reliable performance across a wide array of applications. The manual encompasses a broad spectrum of engine models, identified by numbers such as ECV100-120, H22-80, and HM70-100, among many others, indicating their widespread use and versatility. The purpose of this manual is to provide comprehensive guidance for the maintenance and repair of Tecumseh 4-Cycle L-Head Engines. It details essential procedures including routine servicing, air filter maintenance, and spark plug specifications, along with recommendations for oil type and capacity. The manual also outlines engine storage preparation and typical service intervals, such as initial service after five hours and routine service every 25-50 operating hours. This resource is designed to assist owners, mechanics, and technicians in ensuring the longevity and optimal performance of their Tecumseh engines.