Manouvrable, high-torque chainsaw for improved performance and user comfort perfect for preparing firewood. Extremely high torque over a wide range of speeds. Up to 20% less fuel consumption and up to 50% reduction in emissions compared to a STIHL 2-stroke engine of the same power output without 2-MIX technology.
MS 391 Farm Boss® Chainsaw - 50cm/20''
Displacement cc 64.1 Power output kW/bhp 3.3/4.5 Weight (kg) 6.2 Pre-separation air filtration system
The innovative long-life air filter system greatly extends the service life of the filter. Air routing removes larger particles of dirt, meaning the actual filter has less to do. So the saw can be used for longer without having to clean the filter.
Decompression valve
The decompression valve is part of the easy start-system. The valve should be pressed before starting in order to reduce the compression pressure when starting, as well as the effort needed to pull the starter rope. The decompression valve is semi-automatic, meaning that it must be pressed manually before starting, but then closes automatically.
STIHL 2-MIX Engine
The new 2-MIX engine features an advanced stratified charge system that boosts power, whilst reducing consumption and pollution, significantly lowering unburned hydrocarbons in the exhaust. The result is a cleaner, more fuel efficient engine.
Advanced combustion technology
Four overflow channels swirl the fuel-air mix before ignition, allowing for optimum combustion and highly efficient performance. The result: lower consumption and high torque across a broad rpm range.
Anti-vibration system
Intense vibration at the handles of power tools can lead to longer-term effects of blood vessels in the hands and arms. STIHL have therefore developed an effective anti-vibration system where by the oscillations from the machines engine are dampened which significantly reduces vibrations at the handles.
Compensator
This controller in the carburettor prevents the fuel-air mixture getting richer as the air filter becomes clogged. The correct quantity of fuel is delivered to the carburettor depending on the quantity of air passing through the air filter. This keeps the fuel/air ratio in the combustion mixture constant and hence also the engine power. The filter doesn't need to be cleaned until an appreciable drop in power occurs.
Variable-displacement oil pump
The exact chain oil output can be adjusted maunally for varying conditions, allowing for a reduction of up to 50%.
Single-lever master control
All important functions such as start, choke, throttle and stop are operated via a single lever.
STIHL Ematic-System
The Ematic chain lubrication system ensures pinpoint lubrication of the saw chain links and guide bar rails. When used with STIHL OILOMATIC saw chain, it will provide maximum lubrication, longer wear and less oil consumption than conventional methods of chain lubrication. The Ematic system can reduce bar oil consumption up to 50%.
