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 can provide, but who do not necessarily need the lighter magnesium-alloy construction of a full-professional series saw.
We tested the MS 391 on heavy farm cutting, processing large firewood, and felling medium-to-large timber. Here is the honest breakdown.
At a Glance: Mid-Range Powerhouses
| Feature | Stihl MS 391 | Stihl MS 271 | Husqvarna 460 Rancher |
|---|---|---|---|
| Displacement | 64.1 cc | 50.2 cc | 60.3 cc |
| Power Output | 4.4 bhp | 3.5 bhp | 3.62 bhp |
| Weight | 12.8 lbs | 12.3 lbs | 13.2 lbs |
| Max Bar Length | 25 in | 20 in | 24 in |
Stihl MS 391 Review: Performance and Engine Technology
At the heart of the Stihl MS 391 is a 64.1 cc engine utilizing Stihl proprietary 2-MIX technology. This stratified scavenging system creates a layer of fuel-free air between the burnt charge and the fresh charge, reducing fuel consumption by up to 20% and decreasing 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.
Honest Downside
At nearly 13 lbs (powerhead only), it can be taxing for all-day limbing. It is a large-frame saw—homeowners with small trees may find it overkill. The price is higher than consumer-focused MS series saws.
Who It Is Best For
Those regularly felling trees over 18 inches in diameter or processing cords of oak and hickory. If you are managing large woodlots, the MS 391 offers nearly identical power to the MS 362 at a lower price point.
Chainsaw Safety
The MS 391 is a high-torque machine that demands experienced handling. For those new to power saws, start with a smaller unit to build proper technique before moving to a machine of this caliber.
Always wear full PPE and review our chainsaw safety guide.
Maintenance
The long-life air filtration system with pre-separation uses centrifugal force to eject large dust particles before they reach the filter. In field tests, this triples the maintenance interval compared to standard systems. The decompression valve makes starting manageable despite the large displacement.
For the right bar and chain setup, check our stihl-chainsaw-bar-size-guide-match-your-model-to-the-right-bar-chain.
Gas vs Battery
For sustained heavy cutting in large-diameter hardwoods, no current battery technology matches the MS 391 torque and runtime. If you need to work all day without charging interruptions, gas remains the practical choice. See our gas vs electric chainsaw guide.
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 or processing cords of oak and hickory, the MS 391 is an investment that pays dividends.
SAWOFF Rating: 4.7 / 5
Get out there and cut. Safely.
Frequently Asked Questions
What is the maximum bar length for the Stihl MS 391?
Stihl recommends a range between 16" and 20" for optimal balance, but the 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 uses a standard high-performance carburetor. For microprocessor-controlled engine management, look at the professional M series saws.
Is the MS 391 too big for a first-time owner?
Generally, yes. 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. Stihl MotoMix is recommended for long-term storage and engine longevity.
What is the weight of the MS 391?
The MS 391 powerhead weighs 12.8 lbs (5.8 kg). With bar, chain, and fluids, the total weight is around 16-17 lbs.
Does the MS 391 have a decompression valve?
Yes, the MS 391 includes a decompression valve for easier starting, which is essential given the 64.1cc displacement.
How does the MS 391 compare to the Husqvarna 460 Rancher?
The MS 391 has slightly more displacement (64.1cc vs 60.3cc) and power (4.4 bhp vs 3.62 bhp) than the Husqvarna 460 Rancher. Both are strong competitors in the farm saw class.
Is the MS 391 good for milling?
The MS 391 can handle light milling with a 25-inch bar, but for serious Alaskan mill work, a larger saw like the MS 661 or MS 881 is recommended.
