MS391 Chainsaw (20")

AA5787

Easy-to-manage, high-torque chainsaw for improved performance and user comfort when harvesting wood or sawing firewood. High torque over a wide range of speeds. Up to 20% less fuel consumption and up to 50% lower emissions compared with the previous model without 2-MIX technology.

Decompression valve

The decompression valve is part of the easy starting system. The valve should be pressed before starting to reduce the compression pressure when starting, as well as reducing the effort needed to pull the starter rope. The decompression valve is semi-automatic; it must be pressed manually before starting, but then closes automatically.

Advanced combustion technology

Four overflow channels swirl the fuel-air mix before ignition, allowing for optimum combustion and highly efficient performance. The result is lower fuel consumption and high torque across a broad rpm range.

Anti-vibration system

Intense vibration at the handles of power tools can lead to long-term effects on blood vessels in the hands and arms. Stihl has therefore developed an effective anti-vibration system whereby the oscillations from the machine’s engine are dampened which significantly reduces vibrations at the handles.

Pre-separation air filtration system

Stihl long-life air filtration systems with pre-separation achieve perceptibly longer filter life compared with conventional filter systems. Air drawn in is swirled. The larger, heavier particles are ejected. The pre-cleaned air is routed to the air filter via the pre-separator duct.

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

Allows a precise, demand-based delivery of oil. It’s possible to reduce oil production by up to 50% in the E position. For very long cutting attachments or very dry wood, an additional volume of oil can be added by the user. similar to illustration.

Single-lever master control

All important functions such as start, choke, throttle and stop are operated via a single lever.

Side chain tensioner

The tensioning screw can be found on the side of the chain saw through the sprocket cover. This removes the need for contact with the sharp saw chain.

Ematic chain lubrication 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 by up to 50%.

Tool free filler caps

Special catches on the fuel and oil tanks for easy opening and locking without the need for tools.

Technical specifications

Displacement 64,1 cm³

Power output 3,3/4,5 kW/bhp

Weight 1) 6,2 kg

Power-to-weight ratio 1,9 kg/kW

Sound pressure level 2) 105 dB(A)

Sound power level 2) 117 dB(A)

Vibration level left/right 3) 4/4 m/s²

Saw chain pitch 3/8"

STIHL Oilomatic saw chain type Rapid Micro (RM)