Man looking up at tree holding MS 661 C-M MAGNUM®

Man standing in the woods holding the MS 661 C-M MAGNUM®

Man bucking a tree using MS 661 C-M MAGNUM®

MS 661 C-M MAGNUM®

Name: MS 661 C-M MAGNUM®
Brand: STIHL
SKU: ms661cm
Rating: 4.5792 (183 reviews)

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Suited for use with long guide bars, this fuel-efficient chainsaw was designed for the demanding professional.

Features

STIHL M-Tronic™
Ematic™ Lubrication System
STIHL ElastoStart™
IntelliCarb™ Compensating Carburetor

When professionals need to fell large trees, in large quantities, they reach for the saw they know has the power to get the job done —the MS 661 C-M. Featuring an impressive power-to-weight ratio and STIHL M-Tronic™ engine management technology, the MS 661 C-M chainsaw also delivers less vibration and 20% greater fuel efficiency than the previous model. Other features include a long-life filter system using HD-2 filter elements to provide longer run times between maintenance, an ElastoStart™ handle, and a high output adjustable oiler.

Wrap-handle version available in select areas. See MS 661 R C-M.

Features
- STIHL M-Tronic™ -
  This product features M-Tronic™ (M) - a new generation of Intelligent Engine Management that eliminates the low and high speed carburetor adjustment screws, compensates for dirty air filter and changes in elevation and fuel quality for optimum engine power at all times.
- Ematic™ Lubrication System -
  The Ematic™ guide bar, when used with STIHL OILOMATIC® saw chain, will provide proper lubrication and less oil consumption than conventional methods. The system works because two ramps, strategically placed in the guide bar rail, help contain the flow of oil and direct all lubrication to the sliding faces of the bar and chain links as well as the rivets and driver holes, which in turn can reduce bar oil consumption up to 50%.
- STIHL ElastoStart™ -
  The ElastoStart™ starter handle is an exclusive feature of STIHL. It is a starting grip with a built-in shock absorber that helps reduce the effort when pulling on the starter cord. The ElastoStart™ starter grip noticeably reduces the sudden peak forces (compression) normally felt during cranking. The forces which occur at the grip after the first compression stroke are smoothed out.
- IntelliCarb™ Compensating Carburetor -
  The IntelliCarb™ Compensating Carburetor is designed to automatically adjust the air/fuel ratio when the air filter becomes restricted or partially clogged and maintains the engine’s correct RPM. IntelliCarb™ uses air from the clean side of the air filter to control the diaphragm and flow of fuel. As the air filter becomes dirty and less air is available for the carburetor, the IntelliCarb™ system adjusts the fuel flow to compensate for the decrease in air flow. This is in contrast to typical carburetors that utilize this air from the “dirty” side of the air box.
- STIHL Quickstop® -
  STIHL chainsaws are equipped with a chain stopping system designed to reduce the risk of injury in certain kickback situations. It is called a STIHL Quickstop® chain brake. The STIHL Quickstop® chain brake is designed to stop the rotation of the chain if activated by the operator’s hand or by inertia if the saw kicks back with sufficient force. In some working positions, the STIHL Quickstop® chain brake can be activated by inertia, stopping the chain within fractions of a second.
- HD2 Air Filter -
  The HD2 air filter on this unit is washable, providing extremely long filter life and lowering maintenance costs. The large surface area allows for longer run times between cleanings and high performance even while operating in dusty and dry conditions. Overall, the HD2 air filter provides better protection of the engine compared to standard air filters.
- Bumper Spikes -
  These spikes prevent pull-in and provide better control, making cutting easier.
- Adjustable Automatic Oiler -
  The Adjustable Automatic Oiler allows the user to adjust the lubricant of the guide bar and saw chain for different bar lengths and cutting conditions.
- Decompression Valve -
  The decompression valve, also referred to as 'deco' or 'deco valve', vents compression in the cylinder for easier starting. The decompression valve temporarily reduces the compression in the combustion chamber during cranking and helps reduce the effort needed to pull the starter rope. It is opened manually and closes automatically as soon as the engine fires.
- Lightweight Sprocket Cover with Captive Bar Nuts -
  The sprocket cover is lightweight and the captive bar nuts are held securely in place for efficient saw chain maintenance.
- Side-Access Chain Tensioner -
  The side-access chain tensioner makes it much more convenient for the user to adjust the saw chain with a bar wrench as opposed to the typical location of the guide bar adjustment screw.
- Master Control Lever™ -
  The Master Control Lever™ is an easy to use single lever, operating the choke, starting throttle lock, and on-off switch. The operator must pull the throttle trigger before moving the Master Control Lever™ to the choke position.
- Anti-Vibration System -
  STIHL has developed a system for minimizing the vibration levels of handheld outdoor power equipment. The STIHL anti-vibration system helps reduce operator fatigue and provides a more comfortable working experience.
- Toolless Fuel and Oil Caps with Retainers -
  Simply lift the lever and twist the caps to remove or tighten. There’s no need to use a tool to tighten or loosen.
- Throttle Trigger Lockout -
  This safety feature must be depressed before the trigger can be activated.

Specifications

Questions And Answers

Reviews

Warnings And Safety
Chainsaw Safety and Maintenance - Video
Product Instruction Manual (PDF)
Product Safety Manual (PDF)
STIHL Limited Warranty
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Note: STIHL recommends use of fuel with no more than 10% Ethanol content. Using fuel with greater than 10% Ethanol content may cause damage to your equipment and may void your STIHL warranty.
IMPORTANT SAFETY INFORMATION The occurrence called “kickback” can cause serious or fatal injury. Always read the instruction manual carefully before using your saw. STIHL uses a green and yellow color-coding system to help you select a powerhead, bar and chain combination that complies with the kickback requirements of ANSI Standard B175.1 (gasoline-powered saws) and §30 of UL 1662/ ANSI Standard B175.1 (electric chainsaws). Ask your STIHL dealer about safe operating procedures and the advantages of the STIHL Quickstop® chain brake, STIHL Quickstop® Plus additional chain braking feature, STIHL reduced kickback bars and STIHL low-kickback saw chains.

STIHL recommends the use of green reduced kickback bars and green low kickback chains on all STIHL chainsaws.
Note: STIHL engine products with the Caring for Nature logo are cleaner than EPA Standards for exhaust emissions.
* The actual listed guide bar length can vary from the effective cutting length based on which powerhead it is installed on.
WARNING! Improper use of any power tool may cause serious or fatal injury. Read, understand, and follow carefully the operating and safety instructions in your instruction manual before using such products.

STIHL products sold through U.S. STIHL Dealers are for distribution in the United States only.

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POWER SOURCE	Gas
POWERHEAD WEIGHT	16.5 lbs.
GUIDE BAR LENGTH (Recommended)	25 in.
OILOMATIC® CHAIN	3/8" RS3
CHAIN OIL CAPACITY	13.5 oz.
ENGINE POWER	7.2 bhp
FUEL CAPACITY	28.7 oz.
DISPLACEMENT	91.1 cc
INTENDED USE	Professional