MS 661 Petrol Chainsaw

Name: MS 661 Petrol Chainsaw
Brand: STIHL

Technical details

Displacement	91.1 cm³
Power	5.40 kW
Engine power	7.30 HP
CO2	679 g/kWh
Device weight without refuelling	7.5 kg ¹⁾

Features

The pictures shown are sample photos. The actual appearance of the equipment features and their specific attachment to the product may differ from the pictorial representations, but will have the same functionality.

MANUAL DECOMPRESSION

EFFORTLESS START-UP. The decompression valve makes it easier to start your power tool. When starting, you can allow some of the compressed mixture to escape from the cylinder by opening the valve. This protects the start-up system and reduces the amount of force required on the starter cord.

COMBI LEVER WITH STOP FUNCTION

SIMPLIFIED OPERATION. Only one start position is required on the combi lever. Thanks to the stop function, once the machine is turned off the control lever immediately moves back into the operating position. This allows a warm machine to be restarted immediately.

STIHL M-TRONIC

RELIABLE WORK WITH THE BEST PERFORMANCE. With STIHL M-Tronic, you’ll have the best performance from your work tool from the outset. Fully electronic engine management regulates the ignition timing and fuel metering in all work situations, taking into account external conditions such as temperature, altitude and fuel quality.

HD2 FILTER

INCREASES SERVICE LIFE. The HD2 filter protects your power tool’s engine against even the finest dust, ensuring a longer service life and reduced wear. The filter made from PET material has up to 70% finer pores than fleece and polyamide filters, and is also oil- and water-repellent. This also makes it easier to clean the filter. When needed, the filter cartridge can be easily replaced without tools.

STIHL 2-MIX ENGINE

HIGHLY POWER-EFFICIENT. With the STIHL 2-MIX engine, you can reduce exhaust emissions and fuel consumption, and therefore operating costs. This 2-stroke engine is low-maintenance and uses fuel efficiently even at high power levels. Use a mixture of petrol and engine oil as fuel. The STIHL 2-MIX engine complies with the strict EU Stage V emissions directive.

STIHL ANTI-VIBRATION SYSTEM

FOR MORE PLEASANT WORK. Vibrations can occur when you put your power tools through their paces, and these are particularly noticeable in the grip area. The buffer and spring elements of the STIHL anti-vibration system reduce the transmission of vibrations to the handle area and therefore to your body. The result is that your power tool is more comfortable to hold and your work is much less tiring.

COMPENSATOR

REDUCED MAINTENANCE. The compensator is a control system in the carburettor, which uses pressure compensation to ensure that engine performance, exhaust gas quality and fuel consumption remain virtually constant over a long period of time, despite increasing contamination of the air filter. You do not need to clean the air filter until there is a noticeable drop in performance. This means that you can work for a long time without maintenance.

CAPTIVE NUTS

PROTECTION AGAINST LOSS The nuts are attached to the sprocket cover in a captive manner. This makes it impossible for the nuts to fall off and get lost when the cover is removed.

VARIABLE-DISPLACEMENT OIL PUMP

OIL CONSUMPTION BASED ON NEED. The controlled-delivery oil pump reduces your chainsaw’s oil consumption by up to 50%. To use it, simply select the E position. For very long cutting attachments or very dry wood, an additional oil volume can be set by the user.

SIDE-MOUNTED CHAIN TENSIONING

FOR SIMPLE AND SECURE RE-TENSIONING. Side-mounted chain tensioning allows for protected, easy and quick chain tensioning and replacement. The tensioning screw is inserted laterally through the sprocket cover.

STIHL EMATIC SYSTEM

REDUCES OIL CONSUMPTION. The STIHL Ematic system comprises a STIHL Ematic or Ematic S guide bar, a STIHL Oilomatic saw chain and a controlled-delivery oil pump. It ensures that the chain oil gets to where it is needed for lubrication. This allows you to reduce oil consumption by up to 50%. If you often work in dusty conditions or if you use long guide bars, you can quickly and easily increase the oil quantity at any time with the new oil pump system.

TOOL-FREE FUEL CAP FOR OIL AND FUEL TANKS

QUICK AND EASY TO USE. With tool-free fuel cap, you can open and close oil and fuel tanks in just a few simple steps, thanks to a bayonet closure.

MS 661 C-M Petrol Chainsaw: Extremely powerful 5.4kW professional saw

Right now, as part of our STIHL Autumn Chainsaw promotion, you’ll get a free saw chain and 2-in1 EasyFile worth over £70.00 when you buy this STIHL chainsaw. This offer is valid until 15 December 2025 and may also be available at participating STIHL dealers.

Very powerful high-performance saw with advanced 2-MIX technology and STIHL M-Tronic (M). This electronic engine management system regulates the ignition timing and the fuel supply and automatically registers the external temperature for optimal engine performance, great acceleration and sustained maximum torque. Extremely robust and durable with low vibration levels. Designed for professional use within forestry and big timber harvesting.

Find the correct replacement guide bar and saw chain for your tool with the STIHL bar & chain advisor.

Exterior design of STIHL guide bars are subject to change. Technical specifications remain the same.