The STIHL® MS 661 C‑M MAGNUM® is a high‑output professional chainsaw engineered for extreme forestry, logging, and large‑diameter woodcutting applications. Built to handle continuous high‑load cutting with extra‑long guide bars, this MAGNUM® configuration delivers massive torque, fast acceleration, and consistent performance in the toughest working conditions.

Key Features

• 91.1cc gas-powered engine delivers exceptional torque for heavy‑duty felling and bucking
• 36in guide bar provides maximum reach for large‑diameter timber and demanding forestry work
• MAGNUM® configuration designed for sustained high‑load, professional operation
• STIHL M‑Tronic™ engine management system automatically adjusts for temperature, altitude, and fuel quality
• Decompression valve reduces starting effort on the high‑compression engine
• STIHL® Anti‑Vibration System helps minimize operator fatigue during extended cutting sessions
• Pre‑separation air filtration system extends air filter life and reduces maintenance intervals
• Side‑access chain tensioner allows quick, convenient chain adjustments
• Toolless fuel and oil caps with retainers simplify refueling and routine maintenance

(Model number 1144‑200‑0336)

Why It’s a Smart Pick

The STIHL® MS 661 C‑M MAGNUM® with a 36in bar is a smart pick for professional loggers and forestry crews who need uncompromising cutting power with long‑bar capability. With its massive engine output, intelligent electronic engine management, and MAGNUM®‑grade durability, it’s built to perform reliably in the most demanding felling and bucking applications.

Description:

The MS 661 MAGNUM® professional chainsaw delivers the reliable power and rugged dependability you need for felling, de-limbing, and bucking large diameter trees. This chainsaw features a simple, proven, and non-electronic design. A fuel-efficient engine and low-maintenance air filtration system help keep operating costs low, while the STIHL® Anti-Vibration System reduces fatigue and improves handling when compared to the previous model, even when using long guide bars. The MS 661 MAGNUM® chainsaw is the perfect partner for forestry, municipal, and tree service professionals.

Features:

• Ematic™ Lubrication System
• The Ematic™ guide bar, when paired with the STIHL OILOMATIC® saw chain, delivers optimal lubrication while significantly reducing oil consumption—by up to 50%. Strategically placed ramps in the guide bar rail channel the oil precisely where it’s needed: the sliding faces of the bar, chain links, rivets, and driver holes.
• STIHL ElastoStart™
• This exclusive starter handle features a built-in shock absorber, reducing the effort and peak forces experienced during startup. It smooths out compression forces for more comfortable cranking.
• HD2 Air Filter
• Washable and long-lasting, the HD2 air filter offers a larger surface area for improved airflow and extended maintenance intervals. It’s especially effective in dusty or dry conditions and helps protect the engine better than standard filters.
• IntelliCarb™ Compensating Carburetor
• This system adjusts the air/fuel mixture automatically as the air filter becomes dirty, ensuring consistent RPM and performance. Unlike typical carburetors, IntelliCarb™ draws air from the clean side of the air filter to maintain engine power.
• STIHL Quickstop® Chain Brake
• A critical safety feature, the STIHL Quickstop® chain brake stops chain rotation in certain kickback situations. It can be activated by the operator’s hand or inertia, halting the chain within fractions of a second.
• Bumper Spikes
• These integrated spikes offer greater control and stability while cutting, preventing pull-in and improving operator precision.
• Lightweight Sprocket Cover with Captive Bar Nuts
• The lightweight cover improves handling, while the captive bar nuts ensure efficient and convenient maintenance without the risk of losing parts.
• Adjustable Automatic Oiler
• Easily adjust the oil flow to match different bar lengths and cutting conditions for optimal chain and bar lubrication.
• Decompression Valve
• Reduces cylinder pressure during startup, making it easier to pull the starter rope. The valve closes automatically once the engine fires.
• Side-Access Chain Tensioner
• Conveniently located for easy adjustments with a bar wrench, eliminating the need for direct access to the guide bar adjustment screw.
• Master Control Lever™
• A user-friendly single lever controls the choke, starting throttle lock, and on/off switch, simplifying the starting and operation process.
• STIHL Anti-Vibration System
• Minimizes vibration to reduce operator fatigue and provide a more comfortable experience, even during extended use.
• Toolless Fuel and Oil Caps with Retainers
• Caps can be removed or tightened quickly without tools—just lift the lever and twist—while the retainers prevent loss.
• Throttle Trigger Lockout
• A built-in safety mechanism that must be depressed before the throttle trigger can be activated, reducing the chance of accidental throttle engagement.

Specifications:

• Power Source: Gas
• Weight: 16.5 lbs
• Bar Length (Recommended): 36 inches
• Chain Type: 3/8" RS3 (OILOMATIC®)
• Chain Oil Capacity: 13.5 oz
• Engine Power: 7.2 bhp
• Fuel Capacity: 28.7 oz
• Displacement: 91.1 cc
• Use: Professional