MS 661 C-M - $1,209.95 DSRP


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A professional chainsaw with enhanced fuel efficiency and STIHL M-Tronic™ technology.

Featuring an impressive power-to-weight ratio and STIHL M-Tronic™ engine management technology, the MS 661 C-M is a professional chainsaw designed for felling large diameter trees. With less vibration and 20% greater fuel efficiency than the MS 660, this saw also features a long-life filter system using HD-2 filter elements to provide longer run times between maintenance, an ElastoStart™ handle an...Read More
Print Spec Sheets
MS 661 C-M Specifications
DISPLACEMENT 91.1 cc (5.56 cu. in.)
ENGINE POWER 5.4 kW (7.2 bhp)
POWERHEAD WEIGHT 7.4kg (16.31 lbs.)
FUEL CAPACITY 825 cc (27.9 oz.)
CHAIN OIL CAPACITY 360 cc (12.2 oz.)
GUIDE BAR LENGTHS* (Recommended ranges) 40 to 80 cm (16" to 32")
STIHL recommends #3624 (33 RS3 84) OILOMATIC® saw chain and 25" 3003 000 4030 Ematic™ guide bar combination. The actual listed guide bar length can vary from the effective cutting length depending upon which powerhead it is installed.
Model Features
  • Zoom
    Reduced-Emission Engine Technology - Caring for Nature
    The STIHL Inc. “Caring for Nature” seal identifies its powered products that are more environmentally conscious, producing zero or low exhaust emissions. STIHL Inc. defines “low exhaust emissions” as being cleaner than EPA and/or CARB exhaust emission standards.

    More Information

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    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.

    See it in action!

    More Information

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    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.
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    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.
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    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.
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    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.
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    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.
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    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.
Standard Features
  • Zoom
    Common Features for Chainsaws
    View the features common to many STIHL chainsaws.

Important Information
WARNING! 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 (Q) 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.
* The actual listed guide bar length can vary from the effective cutting length based on which powerhead it is installed on.
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. Learn More…
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.
Click to view the STIHL Limited Warranty Time Periods
We Also Suggest
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    HP Ultra 2-Cycle Engine Oil
    HP Ultra is a fully synthetic 2-cycle engine oil specially suited for high performance chainsaws and power tools. This oil has outstanding engine cleaning characteristics, plus “ultra” superior lubricating qualities in comparison to other 2-cycle engine oils. It is ideal for use in STIHL 4-MIX® engines. This oil is biodegradable, degrading by 80% in 21 days.

    •2.6 oz. bottle makes 1 gallon mix

    •5.2 oz. bottle makes 2 gallon mix

    •6.4 oz. bottle makes 2 1/2 gallon mix

    •12.8 oz. bottle makes 5 gallon mix

    STIHL recommends a mix of 50:1 high-quality 89 octane or higher unleaded gasoline to STIHL engine oil. This same mix ratio should be used during break-in.

  • Bar and Chain Oil Zoom
    Bar and Chain Oil
    STIHL Bar and Chain oil is formulated to adhere to the bar and chain, and to reduce wear. Special agents in the oil formulation help keep sap and pitch from clinging to the bar and chain.

    Available in quart and gallon bottles, 5 gallon pails and 55 gallon drums, in both summer and winter weights.

  • Complete Filing Kits Zoom
    Complete Filing Kits
    Kits available for the following chain types: STIHL PICCO Mini; 1/4" pitch chain; .325" pitch chain; 3/8" pitch chain; .404" pitch chain.
    Includes file guide, depth gauge, round file, flat file and two file handles in tool pouch.
    Chain Pitch File Diameter File Guide
    Part Number
    Sharpening Kit
    Part Number
    in. mm in. mm Part Number
    3/8 PMN 9.32 5/32 4.0 0811 411 8073

    5605 750 4327

    5605 007 1026

    3/8 PM
    5/32 4.0 0811 411 8091

    5605 750 4327

    5605 007 1027

    0.325 8.25 3/16 4.8 0811 412 8088

    5605 750 4328

    5605 007 1028

    3/8 9.32 13/64 5.2 0814 243 3384 5605 750 4329

    5605 007 1029

    0.404 10.26 7/32 5.5 0811 412 8108 5605 750 4330

    5605 007 1030

For Your Safety
  • STIHL Pro Mark™ Series Hi-Vis Zip Chap Zoom
    STIHL Pro Mark™ Series Hi-Vis Zip Chap

    If you are a tree care or emergency service professional working along roadways, we recommend the Pro Mark™ Hi-Vis Zip Chaps. They combine full wrap-around lower leg protection with high-visibility nylon fabric that meets Class E reflective requirements and earns a Class 3 reflective rating when worn with the Class 2 reflective vest. The chaps also feature reflective tapes made from Reflexite Brilliance Series GP-340, making them visible by motorists traveling up to 50 mph. Inside, there are nine layers of Avertic™ Pro by Engtex® cut retardant material, helping reduce the risk or severity of injury in the event of contact with a rotating saw chain on a gasoline-powered chainsaw. Rows of heavy-duty zippers run along the entire inseam of the chaps, helping to ensure they are an effective fit and are easy to put on and/or remove. Stop by our showroom today and check out these versatile chaps.

  • STIHL Pro Mark™ Forestry Helmet System Zoom
    STIHL Pro Mark™ Forestry Helmet System
    The STIHL Pro Mark™ Forestry Helmet System is a premium quality product, designed with NRR 25 hearing protection and adjustable ratchet-style six-point suspension.
  • Outdoor PRO Gloves Zoom
    Outdoor PRO Gloves
    STIHL Outdoor PRO Gloves feature high-quality synthetic leather for comfort and durability. That durability is enhanced further by TPR (thermoplastic rubber)-padded knuckle and finger areas. Yet the gloves remain lightweight and deliver a high degree of dexterity. The material is also breathable for all-day comfort. Feel the difference for yourself – stop by our Dealership and try them on today.

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Rated 4.5 out of 5 by 22reviewers.
Rated 5 out of 5 by Best saw I ever handled When you hold this saw in your hands you instantly know your holding something awesome. I can't pick it up without grinning ear to ear. Well worth the money October 13, 2016
Rated 1 out of 5 by Bad apple? What an absolute piece of junk. Do not buy. I repeat, do NOT buy this chainsaw! Problem after problem from day one. It's had a new cylinder and piston put in it, on top of every single warrantable part replaced. Along with a handful of non-warranty parts. Still doesn't run correctly. Much less, as advertised. Supposed to be a professional level saw yet you could walk into Walmart, buy the cheapest saw they have, and it would be more reliable. Extremely dissatisfied September 7, 2016
Rated 5 out of 5 by Is it wrong to love your saw more than ur wife? goes thru even the hardest wood like a hot knife thru butter July 24, 2016
Rated 5 out of 5 by MS 660 1 year later After 1 year of use I can say the MS 660 is a great saw. Always starts on 1 or 2 pulls, never has needed the choke but you must use the decompression button. I have the 20, 25 and 36 inch bars with Stihl carbide chains, as I cut mostly flood damaged, dirty wood. I have not found a tree that even challenges the saw. After about 4 hours of cutting I may switch to my MS044 as I start to get tired. The MS 660 is heavy but that really does help when cutting a felled tree, just hold the saw and it cuts all by itself. I could not be happier with a chainsaw than I am with my MS660, although my MS044 and 009 rate real close. July 23, 2016
Rated 5 out of 5 by Best saw for your dollar. This saw is the definition of professional. Tough durable and ready for any task when time equals money. July 21, 2016
Rated 5 out of 5 by Power demon I added the ms 661 to my fleet this spring. I previously have owned a ms360, ms461, and a 201T, and an old 015L. The 661 I added mostly for milling, running a 36" bar with milling chains on an MK III mill. I have since put a 28" light weight bar on it, and love it. It walks through everything I have cut. Oak, hickory, walnut, nothing makes it bog. Twice after being shut down I could not get it to restart until it cooled off. I'm assuming it was an issue with the M-tronic while it was breaking in, as it has not happened for about five, or six gallons of fuel through it since. I always run super unleaded with the HP Ultra oil, since I had to rebuild the top end of my 360 after twelve years of cutting at least ten cords of wood a year on top of other work. I would say this is a great saw. I have no hesitation in making recommendations for this saw! July 20, 2016
Rated 5 out of 5 by Great saw I use my MS 661 with my Alaska chainsaw mill to turn timber into lumber on my remote property in Alaska. I make everything from 16' beams to wall studs and planks as thin as 3/4" thick. I use a 20" bar and ripping chain, man does this baby cut! Very fuel efficient and easy to handle. I have been using Sthyl products for over 30 years and have never been let down. July 12, 2016
Rated 5 out of 5 by Priceless I do full time selective harvest low impact logging. Broke in the 13th saw in collection. Bore cut a butt 60 inches wide. Went to the back and finished her off quickly..bucked off the log at 37 feet.35 inches at that height. Cut splits cracks or imperfections..thank you stihl..let's just say this is a good example of 26,000 reasons to buy a stihl!! Sincerely jack the veneer hunter..PS.,the wife made quick work of the limbs with a 441c.. March 27, 2016