Stihl MS 391 Review: Power and Precision for the Modern Landowner
In the landscape of mid-to-high-range chainsaws, the Stihl MS 391 occupies a unique strategic position. Engineered as a high-performance “Farm and Ranch” saw, it is designed for users who require more displacement and torque than entry-level models like the Stihl MS 250 can provide, but who do not necessarily need the lighter, magnesium-alloy construction of a full-professional series saw. For those managing large woodlots, felling medium-to-large timber, or processing massive amounts of firewood, the MS 391 offers a compelling balance of raw power and environmental efficiency.
Quick Comparison: Mid-Range Powerhouses
Before diving into the technical nuances, see how the MS 391 stacks up against its closest competitors in the current market.
| Feature | Stihl MS 391 | Stihl MS 271 | Husqvarna 460 Rancher | Action |
|---|---|---|---|---|
| Displacement | 64.1 cc | 50.2 cc | 60.3 cc | 🛒 Check Price |
| Power Output | 4.4 bhp | 3.5 bhp | 3.62 bhp | 🛒 View on Amazon |
| Weight | 12.8 lbs | 12.3 lbs | 13.2 lbs | 🛒 Buy Now |
| Max Bar Length | 25 in | 20 in | 24 in | 🛒 Check Deals |
Performance and Engine Technology
At the heart of the Stihl MS 391 is a 64.1 cc engine utilizing Stihl’s proprietary 2-MIX technology. This stratified scavenging system creates a layer of fuel-free air between the burnt charge in the combustion chamber and the fresh charge in the crankcase. The result is a significant reduction in fuel consumption—up to 20% compared to traditional two-stroke engines—and a massive decrease in exhaust emissions.
This saw is built for high-torque delivery. Unlike smaller saws that rely on high RPMs to maintain cutting speed, the MS 391 provides a robust torque curve that allows it to pull through dense hardwoods without frequent “bogging.” This makes it an ideal candidate for our list of the best chainsaws 2026 for rural property owners.
🛒 Check Price on AmazonAdvanced Filtration and Maintenance
One of the standout features of the MS 391 is its long-life air filtration system with pre-separation. This system uses centrifugal force to eject large dust and dirt particles before they ever reach the air filter. In practical field tests, this triples the maintenance interval compared to standard systems, ensuring that power remains consistent during long days in the woods.
Ergonomics and Vibration Control
Despite its power, Stihl has integrated an advanced anti-vibration system. By utilizing precisely calculated buffer zones, the saw minimizes the transfer of engine and saw chain oscillations to the handles. This is a critical safety feature; reducing operator fatigue is essential for maintaining control during complex fells. For more on safe operation, consult our chainsaw safety guide.
Hardware Specs & Technical Breakdown
To understand the MS 391’s capabilities, one must look at the raw data:
- Engine Displacement: 64.1 cc (3.91 cu. in.)
- Engine Power: 3.3 kW (4.4 bhp)
- Powerhead Weight: 5.8 kg (12.8 lbs)
- Fuel Capacity: 600 cc (20.3 oz.)
- Oil Capacity: 350 cc (11.8 oz.)
- Chain Pitch: 3/8” RS3
- Recommended Bar Lengths: 16” to 25”
- Decompression Valve: Included for easier starting.
- Side-Access Chain Tensioner: Standard for quick adjustments.
Pros & Cons
Pros
- Exceptional Torque: Handles 20”+ bars in hardwood with ease.
- Eco-Friendly: 2-MIX engine exceeds emission standards without sacrificing power.
- Durability: Built with high-impact polymers and a robust crankcase for farm use.
- Ease of Use: Features a decompression valve and toolless fuel/oil caps.
Cons
- Weight: At nearly 13 lbs (powerhead only), it can be taxing for all-day limbing.
- Size: It is a large-frame saw; homeowners with small trees may find it “overkill.”
- Price: Higher entry point than the consumer-focused MS series.
Final Verdict
The Stihl MS 391 is a “workhorse” in the truest sense. It bridges the gap between the hobbyist and the professional logger. While it lacks the magnesium crankcase of the MS 362, it offers nearly identical power at a significantly lower price point. If you are regularly felling trees over 18 inches in diameter or processing cords of oak and hickory, the MS 391 is an investment that pays dividends in time saved and reliability.
SAWOFF Rating: 4.7/5
🛒 Check Price on AmazonFAQ
What is the maximum bar length for the Stihl MS 391?
While Stihl recommends a range between 16” and 20” for optimal balance, the MS 391’s 64.1cc engine can effectively run a 25-inch bar for occasional large-diameter felling.
Does the MS 391 have an M-Tronic engine?
No, the MS 391 typically uses a standard high-performance carburetor. For users looking for microprocessor-controlled engine management, they would need to look at the professional “i” or “M” series saws.
Is the MS 391 too big for a first-time owner?
Generally, yes. For those new to power saws, we recommend starting with a smaller, more maneuverable unit like the Stihl MS 170 or MS 180 to build proper technique before moving to a high-torque machine like the 391.
What fuel mix should I use?
The MS 391 requires a 50:1 ratio of high-quality 89+ octane gasoline and two-stroke air-cooled engine oil. Using Stihl MotoMix is recommended for long-term storage and engine longevity.