Stihl MS 291 chainsaw

Technical data

• Displacement 55.5 cm³
• Weight 1) 5.6 kg
• Power-to-weight ratio 2.0 kg/kW
• Power output 2.8 kW/3.8 bhp
• Recomm. max. bar length 45 cm
• Vibration levels left/right 2) 4.5/4.5 m/s²
• Oilomatic saw chain pitch/type .325″ RMC
• Sound power level 3) 117.0 dB(A)
• Sound pressure level 3) 103.0 dB(A)
• 1) without bar/chain
• 2) (K) factor according to Dir. 2006/42/EC = 2m/s²
• 3) Power factor according to DIR2006/42/EC=2.5(dB(A))

Reduced-emission engine technology:

2-stroke engine with stratified charge. During the flushing process a fuel-free layer of air is created between the burned charge in the combustion chamber and the fresh charge in the crankcase. This cushion reduces the amount of fuel lost in flushing discharge during the charge cycle. The result? More power with a lower weight, up to 20% lower fuel consumption than regular 2-stroke engines and significantly reduced exhaust emissions.

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.

Pre-separation air filtration system:

The long-life air filter system with cyclone air routing ensures that 80% of dust particles contained in the sucked in air are caught in the first stage of the system. Unlike traditional systems, these are not collected in the foam filter, but are separated and transported out into the surrounding air. In turn, this provides the elimination of cleaning intervals for the foam pre-filter.

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.

Carburettor heating:

By changing the chain saw from summer to winter operation the intake air is pre heated over the engine fins. This ensures that the carburetor does not ice up, and you can continue working in freezing temperatures.

Tool free filler caps:

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

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.

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 up to 50%.

Side chain tensioner:

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

Single-lever master control:

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