This comprehensive workshop service and repair manual provides detailed instructions and high-quality diagrams to help you effectively service and repair your Stihl BR 340, 340 L, SR420, and 420 C backpack blowers. It covers a wide range of topics, including: * **Introduction:** A general overview of the blowers, their components, and safety precautions. * **Specifications:** Detailed technical specifications for each blower model, including engine details, dimensions, and weight. * **Clutch, Chain Drive, Chain Brake & Chain Tensioner:** Step-by-step guidance on inspecting, adjusting, and repairing the chain drive system, including the clutch, brake, and tensioner. * **Engine:** Thorough coverage of engine components, including the cylinder, piston, crankshaft, and connecting rod. Detailed instructions for troubleshooting engine problems, performing maintenance tasks, and making repairs. * **Ignition System:** Clear explanations of the ignition system, including spark plug, ignition coil, and wiring. Instructions for diagnosing and fixing ignition issues. * **Rewind Starter:** Guidance on inspecting, adjusting, and repairing the rewind starter mechanism. * **AV Handle System:** Detailed information on the anti-vibration handle system, including its components and maintenance procedures. * **Master Control / Handle System:** Instructions on operating, adjusting, and repairing the master control and handle system. * **Chain Lubrication:** Explanations of the chain lubrication system, including oil pump, oil lines, and oil tank. Instructions for maintaining and troubleshooting the lubrication system. * **Fuel System:** A complete guide to the fuel system, including carburetor, fuel lines, and fuel tank. Detailed instructions for troubleshooting fuel-related problems and making repairs. * **Special Servicing Tools and Aids:** A listing of specialized tools and aids that may be required for servicing and repairing these blowers. This valuable resource is essential for anyone who wants to maintain and repair their Stihl backpack blowers. It provides clear instructions and detailed diagrams to help you understand the workings of these machines and perform repairs confidently.

The Stihl BR 340, BR 340 L, SR420, and 420 C are a range of powerful backpack blowers renowned for their durability and performance. These models are designed for demanding tasks requiring high air velocity and volume to effectively clear debris, leaves, and other materials from a wide range of areas. The BR 340 and BR 340 L models feature a robust 2-stroke engine with a displacement of 42.4 cc, delivering impressive power and torque. While the SR420 and 420 C models boast a slightly larger 45.6 cc engine, further amplifying their blowing power. All these models offer impressive air velocity ranging from 190 mph to 205 mph, making them ideal for tackling large areas and tough debris. Their lightweight design and ergonomic shoulder straps ensure comfortable operation even during prolonged use. A key feature of these backpack blowers is their versatility. The adjustable air speed controls allow users to tailor the power output to suit the specific task at hand. From clearing light debris to tackling heavy leaves and branches, these blowers can handle it all. The Stihl BR 340 series models are also equipped with a durable blower tube, which can be extended to reach difficult areas or adjusted to direct the air stream precisely. The presence of a multi-function handle further enhances user control, allowing for easy direction and maneuvering of the blower. The Stihl BR 340 series models are built to last, with their high-quality materials and robust construction ensuring reliable performance even under demanding conditions. The manual provides detailed information on the operation, maintenance, and troubleshooting of these powerful backpack blowers, making it an invaluable resource for both professional and hobbyist users.