When professionals need to fell large trees in massive quantities, they reach for the saw built for the heavy lifting: the STIHL MS 661 C-M. This high-performance powerhouse features an impressive power-to-weight ratio and is the go-to choice for large-scale forestry operations. Driven by a massive 91.1 cc engine producing 7.2 bhp, it delivers 20% greater fuel efficiency than previous models while significantly reducing vibration for all-day use.
The MS 661 C-M is equipped with STIHL M-Tronic™ technology, an intelligent engine management system that automatically adjusts to your environment, and a long-life HD2 air filter system that extends run times between maintenance. Designed for the most demanding felling, bucking, and processing jobs, this saw combines raw strength with refined German engineering.
Key Features & Benefits
Intelligent Power & Performance
- STIHL M-Tronic™: Electronically controls ignition timing and fuel metering, eliminating manual carburetor adjustments and compensating for altitude and fuel quality.
- HD2 Air Filter: A washable, large-surface-area filter that provides superior engine protection and dramatically longer intervals between cleanings, even in dusty conditions.
- Adjustable High-Output Oiler: Allows you to increase or decrease oil flow to suit extra-long guide bars or varying wood densities.
Advanced Comfort & Starting
- Anti-Vibration System: Specifically tuned to handle the saw’s high power while minimizing operator fatigue for a smoother cutting experience.
- Decompression Valve: Vents cylinder compression during startup, significantly reducing the force needed to pull the starter rope.
- STIHL ElastoStart™: A built-in shock absorber in the starter handle smooths out the peak forces felt during cranking for a "snap-free" start.
Rugged Durability & Maintenance
- Ematic™ Lubrication System: Reduces bar oil consumption by up to 50% by directing lubrication exactly where it's needed most on the chain and bar rails.
- Captive Bar Nuts: The nuts are secured to the sprocket cover, so you never have to worry about losing them in the brush during field maintenance.
- Side-Access Chain Tensioner: Enables quick and easy chain adjustments using a bar wrench from the side of the housing.
- Toolless Fuel and Oil Caps: Featuring easy-lift levers for fast refills without the need for additional tools.
Technical Specifications
| Intended Use | Professional / Heavy Forestry |
| Displacement | 91.1 cc |
| Engine Power | 7.2 bhp |
| Powerhead Weight | 16.5 lbs. |
| Fuel Capacity | 28.7 oz. |
| Chain Oil Capacity | 13.5 oz. |
| Recommended Bar Length | 25 in. (Supports longer) |
| Chain Type | 3/8" RS3 |
