STIHL® MS 661 C-M Chainsaw

• Bar Length: 71-90 cm
• Bar Length: 28-36" STIHL ROLLOMATIC®
• Displacement: 91.1 cm³
• Power Output: 5.4/7.3 kW/HP
• Weight: 7.5 kg 1)
• Power-to-Weight Ratio: 1.4 kg/kW
• Weight: 9.22 / 10.38 kg 2)
• Length with Bumper Strike: 467 mm
• Sound Pressure Level: 105 dB(A) 3)
• Sound Power Level: 118 dB(A) 3)
• Vibration Values Left/Right: 6.9/5.6 m/s² 4)
• Saw Chain Pitch: 3/8" STIHL RAPID™
• CO₂ Emissions: 679 g/kWh

What is the STIHL MS 661 R MAGNUM chainsaw?
The STIHL MS 661 R MAGNUM is a high-output professional chainsaw built for forestry, large timber harvesting, felling and heavy-duty limbing.

Who is the STIHL MS 661 R MAGNUM designed for?
It is designed for experienced forestry professionals, loggers and commercial operators working with large-diameter timber.

How powerful is the STIHL MS 661 R MAGNUM?
It has a 91.1cc engine and produces approximately 5.4 kW, or 7.3 HP.

What is STIHL M-Tronic?
STIHL M-Tronic is an electronic engine-management system that automatically adjusts ignition timing and fuel delivery based on temperature, altitude, fuel quality and operating conditions.

What are the benefits of STIHL M-Tronic?
It helps provide easier starting, strong acceleration and consistent maximum performance without frequent manual carburetor adjustments.

What is STIHL 2-MIX technology?
STIHL 2-MIX is a two-stroke engine design intended to improve fuel efficiency and reduce exhaust emissions while maintaining high power output.

What bar lengths are available for the MS 661 R MAGNUM?
The supplied specifications list 28-inch to 36-inch STIHL Rollomatic guide bars.

Which guide bar is supplied with this saw?
This configuration is supplied with a STIHL Rollomatic E guide bar, not the Rollomatic ES Light bar shown in some product images.

What does the R in MS 661 R MAGNUM mean?
The R configuration includes a wrap handle for additional gripping positions.

What are the benefits of the wrap handle?
It allows the operator to keep both hands in suitable positions while felling or limbing from different angles.

Is the MS 661 R MAGNUM suitable for large trees?
Yes. Its 91.1cc engine, high power output and long-bar compatibility make it suitable for large-diameter timber.

What chain pitch does the MS 661 R MAGNUM use?
It uses a 3/8-inch STIHL Rapid chain configuration.

How much does the STIHL MS 661 R MAGNUM weigh?
The powerhead weighs approximately 7.5 kg before fuel, bar and chain are added.

What is the power-to-weight ratio?
The listed power-to-weight ratio is approximately 1.4 kg per kW.

What is the decompression valve?
The decompression valve releases some cylinder pressure during startup, reducing the force required to pull the starter cord.

What is STIHL ElastoStart?
STIHL ElastoStart uses a damping element in the starter handle to reduce sudden force peaks during starting.

What is the STIHL Master Control Lever?
The Master Control Lever combines key starting and operating functions into a single control.

What does the stop function do?
After the saw is switched off, the control automatically returns to the operating position so a warm engine can be restarted quickly.

What type of air filter does the MS 661 R MAGNUM use?
It uses an HD2 air filter designed to capture fine dust while resisting oil and water.

Can the HD2 filter be cleaned?
Yes. The filter is designed for easy cleaning and uses a quick-release system for tool-free removal.

Is the STIHL MS 661 R MAGNUM low vibration?
It is designed with vibration reduction, although the listed vibration values are 6.9 m/s² on the left handle and 5.6 m/s² on the right.

How loud is the STIHL MS 661 R MAGNUM?
The listed sound pressure level is approximately 105 dB(A), with a sound power level of approximately 118 dB(A).

What fuel does the MS 661 R MAGNUM use?
It uses a mixture of gasoline and approved two-stroke engine oil prepared according to STIHL specifications.

Is the STIHL MS 661 R MAGNUM suitable for beginners?
No. Its power, weight and long-bar capability make it best suited to trained and experienced chainsaw operators.

What maintenance does the MS 661 R MAGNUM require?
Routine maintenance includes cleaning the air filter, sharpening and tensioning the chain, checking bar lubrication, inspecting the sprocket and servicing the engine according to STIHL’s schedule.

What safety equipment should be worn?
Use a helmet, eye and hearing protection, gloves, chainsaw protective legwear and suitable safety boots.

What are the main benefits of the STIHL MS 661 R MAGNUM?
Its main benefits include a 91.1cc professional engine, M-Tronic management, STIHL 2-MIX technology, wrap-handle control and compatibility with 28-inch to 36-inch bars.

Where can I buy the STIHL MS 661 R MAGNUM chainsaw in Canada?
The STIHL MS 661 R MAGNUM chainsaw is available in store from Arns Equipment in Calgary or online across Canada at arns.ca.