MS 391 - $549.95 DSRP


Our top-of-the-line chainsaw for farm and ranch.

With an advanced low-emission engine technology, the STIHL MS 391 mid-range chainsaw improves fuel efficiency by up to 20% compared to previous models. The new air filtration system requires fewer filter changes, allowing for longer run times. Improved fuel efficiency and fewer filter changes save you time and money.

Print Spec Sheets
MS 391 Specifications
DISPLACEMENT 64.1 cc (3.9 cu. in.)
ENGINE POWER 3.3 kW (4.4 bhp)
POWERHEAD WEIGHT 6.2 kg (13.67 Ibs.)
FUEL CAPACITY 600 cc (20.3 oz.)
CHAIN OIL CAPACITY 350 cc (11.8 oz.)
OILOMATIC® CHAIN 3/8" RS3
GUIDE BAR LENGTHS* (Recommended ranges) 40 to 50 cm (16" to 20")
STIHL ROLLOMATIC®
POWER SOURCE Gas
STIHL recommends #3624 (33 RS3 72) OILOMATIC® saw chain and 20" 3003 008 8921 Ematic™ guide bar combination. The actual listed guide bar length can vary from the effective cutting length depending upon which powerhead it is installed.
Model Features
  • Zoom
    Reduced-Emission Engine Technology - Caring for Nature
    The STIHL Inc. “Caring for Nature” seal identifies its powered products that are more environmentally conscious, producing zero or low exhaust emissions. STIHL Inc. defines “low exhaust emissions” as being cleaner than EPA and/or CARB exhaust emission standards.

    More Information

Standard Features
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    Common Features for Chainsaws
    View the features common to many STIHL chainsaws.
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    Pre-Separation Air Filtration System
    This time-saving technology boosts the efficiency of the engine’s filter system, doubling the time between air filter cleanings. Air drawn into the engine is first separated via centrifugal force, ejecting the heavier dirt particles before being routed to the air filter. This pre-separation means less dirt to be captured by the air filter, resulting in less frequent cleaning and maintenance.

    More Information

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    Anti-Vibration System
    STIHL has developed a system for minimizing the vibration levels of handheld outdoor power equipment. The STIHL anti-vibration system helps reduce operator fatigue and provides a more comfortable working experience.
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    IntelliCarb™ Compensating Carburetor
    The IntelliCarb™ Compensating Carburetor is designed to automatically adjust the air/fuel ratio when the air filter becomes restricted or partially clogged and maintains the engine’s correct RPM. IntelliCarb™ uses air from the clean side of the air filter to control the diaphragm and flow of fuel. As the air filter becomes dirty and less air is available for the carburetor, the IntelliCarb™ system adjusts the fuel flow to compensate for the decrease in air flow. This is in contrast to typical carburetors that utilize this air from the “dirty” side of the air box.
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    Side-Access Chain Tensioner
    The side-access chain tensioner makes it much more convenient for the user to adjust the saw chain with a bar wrench as opposed to the typical location of the guide bar adjustment screw.
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    Toolless fuel and oil caps with retainers
    Simply lift the lever and twist the caps to remove or tighten. There‘s no need to use a tool to tighten or loosen.

Important Information
WARNING! The occurrence called “kickback” can cause serious or fatal injury. Always read the instruction manual carefully before using your saw. STIHL uses a green and yellow color-coding system to help you select a powerhead, bar and chain combination that complies with the kickback requirements of ANSI Standard B175.1 (gasoline-powered saws) and §30 of UL 1662/ ANSI Standard B175.1 (electric chainsaws). Ask your STIHL dealer about safe operating procedures and the advantages of the STIHL Quickstop® chain brake, STIHL Quickstop® Plus (Q) additional chain braking feature, STIHL reduced kickback bars and STIHL low-kickback saw chains.

STIHL recommends the use of green reduced kickback bars and green low kickback chains on all STIHL chainsaws.
* The actual listed guide bar length can vary from the effective cutting length based on which powerhead it is installed on.
Note: STIHL recommends use of fuel with no more than 10% Ethanol content. Using fuel with greater than 10% Ethanol content may cause damage to your equipment and may void your STIHL warranty. Learn More…
WARNING! Improper use of any power tool may cause serious or fatal injury. Read, understand and follow carefully the operating and safety instructions in your instruction manual before using such products.

STIHL products sold through U.S. STIHL Dealers are for distribution in the United States only.
Click to view the STIHL Limited Warranty Time Periods
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    HP Ultra 2-Cycle Engine Oil
    HP Ultra is a fully synthetic 2-cycle engine oil specially suited for high performance chainsaws and power tools. This oil has outstanding engine cleaning characteristics, plus “ultra” superior lubricating qualities in comparison to other 2-cycle engine oils. It is ideal for use in STIHL 4-MIX® engines. This oil is biodegradable, degrading by 80% in 21 days.

    •2.6 oz. bottle makes 1 gallon mix

    •5.2 oz. bottle makes 2 gallon mix

    •6.4 oz. bottle makes 2 1/2 gallon mix

    •12.8 oz. bottle makes 5 gallon mix

    STIHL recommends a mix of 50:1 high-quality 89 octane or higher unleaded gasoline to STIHL engine oil. This same mix ratio should be used during break-in.

  • Bar and Chain Oil Zoom
    Bar and Chain Oil
    STIHL Bar and Chain oil is formulated to adhere to the bar and chain, and to reduce wear. Special agents in the oil formulation help keep sap and pitch from clinging to the bar and chain.

    Available in quart and gallon bottles, 5 gallon pails and 55 gallon drums, in both summer and winter weights.

  • Woodsman Chainsaw Carrying Case Zoom
    Woodsman Chainsaw Carrying Case
    Woodsman carrying case. Unique, removable bar scabbard has built-in tool holders to carry tools to the cutting site. Fits MS 170 to MS 460 M with 20" bar.

    Replacement latches and scabbard are available.

  • Complete Filing Kits Zoom
    Complete Filing Kits
    Kits available for the following chain types: STIHL PICCO Mini; 1/4" pitch chain; .325" pitch chain; 3/8" pitch chain; .404" pitch chain.
    Includes file guide, depth gauge, round file, flat file and two file handles in tool pouch.
    Chain Pitch File Diameter File Guide
    Part Number
    Sharpening Kit
    Part Number
    in. mm in. mm Part Number
    3/8 PMN 9.32 5/32 4.0 0811 411 8073

    5605 750 4327

    5605 007 1026

    1/4
    3/8 PM
    6.35
    9.32
    5/32 4.0 0811 411 8091

    5605 750 4327

    5605 007 1027

    0.325 8.25 3/16 4.8 0811 412 8088

    5605 750 4328

    5605 007 1028

    3/8 9.32 13/64 5.2 0814 243 3384 5605 750 4329

    5605 007 1029

    0.404 10.26 7/32 5.5 0811 412 8108 5605 750 4330

    5605 007 1030

For Your Safety
  • Anti-Vibration Gloves Zoom
    Anti-Vibration Gloves
    Reduced vibration from handheld machines. Meets ISO 10819.1996 and ANSI S2.73 vibration standards TRM 72 and TRN 55.

    Sizes available: L, XL
  • Forestry Helmet System Zoom
    Forestry Helmet System
    Adjustable hearing protection. Epoxy-coated full face screen. Tough ABS hard hat meets ANSI Z89.1-2003 Type 1 Class G. All parts are replaceable.

STIHL Dealer Days are Happening Now!

MS 391 is rated 4.5 out of 5 by 226.
Rated 5 out of 5 by from Cut like a dream I have just about every budget saw known to man. This is a much better product by far. Fell 5 trees with it so far and one giant oak that fell on its own. Started every time and flies threw everything I have thrown at.
Date published: 2017-04-09
Rated 5 out of 5 by from Great powerful saw Ok, I've had the saw for 3-4 years now and used it each year.Saw really woke up after the first couple hours of use.With a sharp chain it chews through pretty quick...even hard maple.Starting after few months of storage isn't an issue...may take 3 -4 pulls and stall out if cold weather. Then starts and runs fine. Typically starts 1 pull after been run and warmed up.Most people problems with small engine equipment is ETHANOL fuel and /or improper gas/oil mix.Before owning any small engine equipment, find a gas station that sell ethanol-free. Get a can just for ethanol free. Trust me folks, pay the extra couple bucks. Your lawn/small engine gear will last much longer, run stronger, and you wont have expensive carb problems after sitting all winter.This saw with a 20" bar will tire you out if you're not use to wielding this lightsaber all day.
Date published: 2017-04-08
Rated 2 out of 5 by from Great saw... as long as the ignition module works. Bought this saw for my father as he cuts alot of wood on his farm for heating the house. Lots of hickory, oak, ash, etc. So I wanted to get a good strong chainsaw that would cut quickly through these woods and then he could use the lighter saws for small stuff. I chose Stihl because of the reputation for service and quality. Not long after we got the saw we put it to work. Break-in went well and the saw performed as expected and better. It was actually a pleasure after using some... lesser saws... to cut large logs to use one that was meant to do the job. Saw started easily, ran well, and we were pleased. Until a few months later, that is.For some reason the saw wouldn't start. I have to say that we always follow manufacturers' recommendations for oil types, service intervals, operating procedures, etc., especially with brands and equipment we aren't familiar with. After a few go around with local service folks about starting it incorrectly, improper fueling, etc., we took it in for service. Since it was under warranty they weren't exactly happy to see us, but eventually they took a look at it and figured out the ignition module was bad. After replacing it the saw worked just fine again.All would have been well if that had been the only time it happened, BUT this has happened at least 4 other times. I purchased the saw in 2013 as a gift for my dad. After the 3rd time Stihl replaced the entire power head at no charge. It has happened twice again since then. This last time the tech replaced only the spark plug and returned a non-functioning chainsaw to my father. My father, no slouch in home small-engine repair, got fed up with the service and bought a non-OEM ignition module and put it in himself. Hopefully this will end the problems.So in all, we are thoroughly disappointed at the reliability of the saw in general. Performance is good, but what use if a good performing machine if you can't even use it? I don't know if it's just the MS391 that has these issues, or if a bad batch if ignition modules came through, or what is going on. I know my father stores the chainsaw in it's case in the barn, so saying it is improperly stored is ridiculous, especially after watching plenty of other people with Stihls do almost no maintenance, keep them in the back of their pickup with no case, and use them day in and out with no problems. Might be a bad model, might be a bad module design, either way be very careful with what you spend your money on.
Date published: 2017-04-06
Rated 5 out of 5 by from This is a well engineered saw This is a well engineered saw. When broken in and start very well. A little on the heavy side for an old man cutting wood all day .
Date published: 2017-03-21
Rated 5 out of 5 by from Awesome power and dependability I run a 25" bar on my 391 and it has no trouble chewing through 24" hickory. I run VP 50:1 premix and it really perks up the saw and no smoke at all.
Date published: 2017-03-20
Rated 5 out of 5 by from The saw is worth every Penny. I heat my home on wood and cut many cords each year. I have been using cheap saws in the past and finally decided to purchase a Stihl. I did a lot of research and found that the ms391 is exactly what I needed. It comes with the 20" bar but you are able to put up to a 28" bar on it. This is a selling selling point for me as I have some rather large trees on my property. The comparison to the pro series was also an easy sell. The biggest difference for me was the weight ratio. The pro series is only slightly lighter. So far in the 3 weeks I've had the saw, I've already cut down over 20 trees and have not had one issue.
Date published: 2017-03-15
Rated 5 out of 5 by from Works great. Sure wish I would have got a case for the saw for the price.
Date published: 2017-03-09
Rated 5 out of 5 by from Awesome saw - eight years strong. I purchased my 391 early in 2009. This saw has not missed a beat since I purchased it. I once tried ethanol-free gas and the saw wouldn't run on it. I literally dumped the tank of gas out, dumped the rest of the remaining gallon out of my gas can, and refilled it with regular high octane gas mixed 50-1 and it hasn't missed a beat since. When starting this saw, lock it on full choke and pull it once or twice until you hear it fire. Take the choke off and pull it again and it will fire every time. I have never struggled to start this saw in the time I've had it. Within the last two weeks I've cut about four cords of wood with it. One winter a few years ago, I cut two log truck loads of trees with it which ranged up to over 20" in diameter. This saw has performed flawlessly for eight years. I may never own another chainsaw.
Date published: 2017-02-25
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