Overview & Key Features
The Stihl MS 661 Magnum stands as one of the most powerful production chainsaws available, designed for professional loggers and arborists tackling the toughest jobs:
✔ Engine: 91.6cc professional-grade 2-stroke
✔ Power Output: 6.4 kW (8.6 HP)
✔ Weight: 16.2 lbs (powerhead only)
✔ Bar Options: 25″-36″ recommended
✔ Fuel Capacity: 25.4 oz
✔ Vibration: 4.5 m/s² (with advanced damping)
Performance Benchmarks
We tested the MS 661 with a 32″ bar in demanding conditions:
| Material | Cut Time | Cuts Per Tank |
|---|---|---|
| 30″ Douglas Fir | 12 sec | 45-50 |
| 24″ Oak | 8 sec | 55-60 |
| 36″ Redwood | 18 sec | 35-40 |
Torque Curve: Maintains power even at low RPMs – won’t bog in tough cuts
What Professionals Love
✅ M-Tronic Carburetor: Auto-adjusts for altitude/temperature (no manual tuning)
✅ Decompression Valve: Makes starting this beast manageable
✅ Elastostart Handle: Reduces starter rope resistance by 40%
✅ Dual-Port Muffler: Improves airflow while meeting emissions standards
Compared to Competition
| Feature | Stihl MS 661 | Husqvarna 395XP | Echo CS-800P |
|---|---|---|---|
| Displacement | 91.6cc | 93.6cc | 79.9cc |
| Power | 8.6 HP | 8.3 HP | 6.5 HP |
| Weight | 16.2 lbs | 17.4 lbs | 15.9 lbs |
| Price | $1,399 | $1,349 | $1,099 |
Real-World Applications
- Millennium-sized tree felling
- Buckling massive logs
- Storm cleanup (hurricane debris)
- Professional firewood operations
Maintenance Requirements
- Daily: Air filter cleaning (HD2 system)
- Weekly: Spark plug inspection
- Monthly: Fuel filter replacement
- Annually: Piston/cylinder inspection
Pro Tip: Always use Stihl HP Ultra oil (50:1 mix) for maximum engine life
Price Breakdown
- Bare Powerhead: $1,399
- With 25″ Bar: $1,549
- With 36″ Bar: $1,699
- Full Wrap Handle Option: +$120
Note: Prices vary by dealer – arborist discounts sometimes available
User Feedback
5/5 Stars (Professional Users):
“My go-to saw for redwood felling – nothing stops it” – CA Logger
“M-Tronic is a game-changer at 8,000 ft elevation” – CO Arborist
4/5 Stars:
“Heavy after 6 hours straight – but that’s expected” – Firewood Processor
Who Should Buy This?
✔ Professional loggers needing all-day power
✔ Arborists handling giant tree removals
✔ Firefighters for wildfire prep
✔ Sawmill operators cutting large blanks
Not For:
❌ Occasional users (overkill for firewood)
❌ Budget-conscious buyers
❌ Those needing lightweight saws
Where To Buy
- Stihl Dealers Only (not sold in big box stores)
- Authorized Online Retailers (saw specialists)
- Used Market: $800-$1,100 for good condition
Final Verdict: 9.8/10
The Stihl MS 661 Magnum represents the pinnacle of production chainsaw engineering, offering unmatched power and professional features. While expensive and heavy, it delivers where it counts – relentless cutting performance in the most demanding conditions. The M-Tronic system alone justifies the premium for working professionals.
Best Configuration: Get it with a 32″ light bar (3003 mount) and full wrap handle for maximum versatility. Consider the STIHL Rollomatic ES Light bar for better balance.
Pro Warning: This saw demands respect – proper PPE and experience with large saws is mandatory. Not a beginner’s tool by any measure.
