STIHL MS 661 C-M Professional Chainsaw 7.3 HP M-Tronic Forestry Saw 16-36 Inch Bar

Maximum Power for Professional Forestry and Logging

The STIHL MS 661 C-M Professional Gas Chainsaw is one of STIHL’s most powerful production chainsaws, engineered specifically for professional forestry crews, loggers, arborists, and demanding commercial applications. Designed to tackle large-diameter hardwoods and intensive cutting operations, the MS 661 C-M combines raw cutting power with advanced technology and professional-grade durability.

At the heart of this powerhouse is a high-performance 91.1cc engine producing 7.3 horsepower (5.4 kW), delivering exceptional torque and cutting speed even in the most challenging conditions. Whether felling large timber, processing hardwood logs, or working with extended guide bars, the MS 661 C-M provides the power and reliability professionals require every day.

Featuring STIHL’s advanced M-Tronic™ electronic engine management system, the chainsaw automatically adjusts engine performance based on operating conditions such as temperature, altitude, fuel quality, and air filter condition. This ensures maximum power output, easier starting, optimized fuel consumption, and consistent cutting performance without manual carburetor adjustments.

Built for intensive professional use, the MS 661 C-M also incorporates a long-life HD2 air filtration system, anti-vibration technology, high-output adjustable oiler, and heavy-duty construction designed to withstand years of demanding forestry work.

Key Features & BenefitsExtreme Professional Cutting Power

• High-output 91.1cc two-stroke engine
• Produces 7.3 HP (5.4 kW)
• Exceptional torque for large timber applications
• Designed for professional forestry and logging operations

STIHL M-Tronic™ Intelligent Engine Management

• Automatically adjusts engine settings in real time
• Optimizes fuel delivery and ignition timing
• Compensates for altitude, temperature, and fuel quality
• Delivers maximum performance without manual tuning

Outstanding Power-to-Weight Ratio

• Professional-grade design balances power and maneuverability
• Exceptional cutting performance relative to weight
• Reduces operator fatigue during extended use
• Improves productivity in demanding environments

Long-Life HD2 Air Filtration System

• Washable HD2 air filter
• Superior engine protection in dusty conditions
• Longer operating intervals between maintenance
• Lower maintenance costs and improved reliability

Built for Large Timber and Hardwood Cutting

• Compatible with guide bars from 16″ to 36″
• Ideal for felling large trees and processing hardwood
• Professional-grade 3/8″ chain system
• Designed for high-volume commercial cutting

Adjustable Automatic Oiler

• High-output oiling system
• Adjustable lubrication levels
• Supports longer guide bars effectively
• Improves chain and guide bar longevity

Reduced Vibration for Greater Comfort