MS 391 Petrol Chainsaw
Excellent chainsaw for heavy agricultural use
Overview
Easy-to-manage, high-torque chainsaw for improved performance and user comfort when harvesting wood or sawing firewood. High torque over a wide range of speeds. Up to 20% less fuel consumption and up to 50% lower emissions compared with the previous model without 2-MIX technology.
Instruction is necessary to recognize or assess the dangers of a chainsaw. Please wear protective clothing and equipment.
If anything is unclear, we recommend to order the chainsaw via Click & Collect and pickup up the chainsaw from a STIHL servicing dealer.
You can find videos showing you how to fill your machine with fuel and oil, fit bars and chains and start your chainsaw here.
Versions
Price-
MS 391 - 40 cm / 16"£924.00*
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MS 391 - 45 cm / 18"£936.00*
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MS 391 - 50 cm / 20"£948.00*
* Manufacturer's recommended retail price updated as of May 2022. The manufacturer's recommended retail prices are subject to change without notice.
The version(s) available in each country may differ from the above range and specifications; specific details may be subject to change without notice. Please ask your local STIHL Approved Dealer for further information.
Technical data

Technical data
Technical data | Value |
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Displacement cm³ | 64.1 |
Power output kW/bhp | 3.3/4.5 |
Bar length cm | 40-50 |
Bar length " | 16-20 |
Weight kg 1) | 6.2 |
Weight kg 2) | 7.28 / 7.51 / 7.68 |
Power-to-weight ratio kg/kW | 1.9 |
Sound pressure level dB(A) 3) | 105 |
Sound power level dB(A) 3) | 117 |
Vibration values left/right m/s² 4) | 4/4 |
STIHL Oilomatic saw chain pitch/type | 3/8" RM |
STIHL Oilomatic saw chain pitch/type | 3/8 " |
Oil pump | Not adjustable |
Tank volume l | 0.60 |
Chain pitch | 3/8" |
Chain tensioning | Side chain tension |
Sprocket - number of teeth | 7 |
Filter | Round cartridge filter |
Filter material | Flocked |
Bumper spike | Steel claw |
Cylinder | Chrome |
Oil tank volume cm3 | 350 |
Sprocket | Sprocket profile |
Anti vibration system | Standard AV-System |
Filler cap | Tools |
EPA Certified fuel consumption l/h | 1.779 |
CO2 g/kWh | 755 |
Handle type | Standard handle |
Exhaust | Standard muffler |
Carburettor | Compensator / Limiter Caps / scavenging / Carburetor |
Speed at maximum power rpm | 9.500 |
Additional features | Ematic chain lubrication system |
EPA Certified fuel consumption glh | 0.47 |
1) Without fuel, without bar and chain
2) Without fuel, with bar and chain
3) K-factor according to DIR 2006/42/EC = 2.5 dB (A)
4) K-factor according to DIR 2006/42/EC = 2m / s ²
The version(s) available in each country may differ from the above range and specifications; specific details may be subject to change without notice. Please ask your local STIHL Approved Dealer for further information.
Features

Standard features
The version(s) available in each country may differ from the above range and specifications; specific details may be subject to change without notice. Please ask your local STIHL Approved Dealer for further information.
Cutting Attachments

Cutting Attachments
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Rollomatic E
The body is made of 3 electrically-welded metal plates, the middle plate is extensively hollowed out. Low weight, high stability.
Technical data Value Bar length 40cm/16",45cm/18",50cm/20" Sprocket pitch 9.32mm/3/8" Number of teeth on the sprocket 10 Pitch 3/8 Inch Groove width 1.6 mm Groove width 1.6mm/.063" Number of teeth 10 Bar type Stern-Rollomatic Bar connection 3.003 Versions
Price- Rollomatic E, 3/8", 1.6 mm, 40 cm / 16" £57.78*
* Manufacturer's recommended retail price updated as of May 2022. The manufacturer's recommended retail prices are subject to change without notice.
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Rollomatic E
The body is made of 3 electrically-welded metal plates, the middle plate is extensively hollowed out. Low weight, high stability.
Technical data Value Bar length 40cm/16",45cm/18",50cm/20" Sprocket pitch 9.32mm/3/8" Number of teeth on the sprocket 10 Pitch 3/8 Inch Groove width 1.6 mm Groove width 1.6mm/.063" Number of teeth 10 Bar type Stern-Rollomatic Bar connection 3.003 Versions
Price- Rollomatic E, 3/8", 1.6 mm, 45 cm / 18" £61.00*
* Manufacturer's recommended retail price updated as of May 2022. The manufacturer's recommended retail prices are subject to change without notice.
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Rollomatic E
The body is made of 3 electrically-welded metal plates, the middle plate is extensively hollowed out. Low weight, high stability.
Technical data Value Bar length 40cm/16",45cm/18",50cm/20" Sprocket pitch 9.32mm/3/8" Number of teeth on the sprocket 10 Pitch 3/8 Inch Groove width 1.6 mm Groove width 1.6mm/.063" Number of teeth 10 Bar type Stern-Rollomatic Bar connection 3.003 Versions
Price- Rollomatic E, 3/8", 1.6 mm, 50 cm / 20" £64.20*
* Manufacturer's recommended retail price updated as of May 2022. The manufacturer's recommended retail prices are subject to change without notice.
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Rapid Micro (RM)
Good all-round comfort chain with low vibration levels, smooth cutting behaviour and low chatter.
Technical data Value Pitch 3/8 inch Drive link gauge 1.6 mm Drive link thickness 1.6mm/.063" Chain pitch 9.32mm/3/8" Required File size 5.2mm / 13/64" Versions
Price- Rapid Micro (RM) 3/8", 1.6 mm, 60 drive links, 40 cm / 16" £39.06*
* Manufacturer's recommended retail price updated as of May 2022. The manufacturer's recommended retail prices are subject to change without notice.
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Rapid Micro (RM)
Good all-round comfort chain with low vibration levels, smooth cutting behaviour and low chatter.
Technical data Value Pitch 3/8 inch Drive link gauge 1.6 mm Drive link thickness 1.6mm/.063" Chain pitch 9.32mm/3/8" Required File size 5.2mm / 13/64" Versions
Price- Rapid Micro (RM) 3/8", 1.6 mm, 66 drive links, 45 cm / 18" £42.48*
* Manufacturer's recommended retail price updated as of May 2022. The manufacturer's recommended retail prices are subject to change without notice.
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Rapid Micro (RM)
Good all-round comfort chain with low vibration levels, smooth cutting behaviour and low chatter.
Technical data Value Pitch 3/8 inch Drive link gauge 1.6 mm Drive link thickness 1.6mm/.063" Chain pitch 9.32mm/3/8" Required File size 5.2mm / 13/64" Versions
Price- Rapid Micro (RM) 3/8", 1.6 mm, 72 drive links, 50 cm / 20" £46.44*
* Manufacturer's recommended retail price updated as of May 2022. The manufacturer's recommended retail prices are subject to change without notice.
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The version(s) available in each country may differ from the above range and specifications; specific details may be subject to change without notice. Please ask your local STIHL Approved Dealer for further information.
Accessories

Accessories
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HP Super 2-stroke engine oil
Semi-synthetic oil with low-ash additives for clean low-smoke burning. 'Low-smoke oil' performance class: JASO-FD, ISO-L-EGD. Fuel/oil ratio: 50:1. Particularly recommended for STIHL 4-MIX engines. Recommended for STIHL 4-MIX engines.
Versions
Price- HP Super 2-stroke engine oil - 1 l (for 50 l) metering bottle £18.62*
* Manufacturer's recommended retail price updated as of May 2022. The manufacturer's recommended retail prices are subject to change without notice.
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MotoMix
STIHL MotoMix is our patented premixed fuel, specially blended for ultimate performance.
This 50:1 ready-mixed fuel is a combination of premium non-ethanol, high-octane motor fuel for all STIHL 2-stroke engines which gives you optimum performance, excellent cold start properties, maximum acceleration over the entire rpm range and perfect running characteristics even with a sudden rev change.
MotoMix uses STIHL HP ultra-premium oil for exceptional engine lubrication and extreme cleanliness. It’s fully synthetic and biodegradable for optimal performance and long service life. MotoMix is user- and engine-friendly thanks to fewer emissions (free from ethanol; almost no olefins and aromatic compounds).
Can be kept in storage for up to five years.
Did you know:
- For MotoMix drums (55 l & 200 l), speak with your nearest STIHL Approved Dealer about direct delivery of the fuel to your preferred address. Find out more about our MotoMix promotion here.
Patent EP 2031043
Technical data Value Octane number >95 RON Octane rating 93 MOZ Benzene content 0.03 % Vol. Sulphur content 3 mg/kg Shelf life up to 5 Years Density at 15°C 690 kg/m3 Olefin content 0.1 % Vol. Vapour pressure at 40 °C 61 kPA Two-stroke oil content 1.8 % Vol. Versions
Price- MotoMix 5 l £21.99*
* Manufacturer's recommended retail price updated as of May 2022. The manufacturer's recommended retail prices are subject to change without notice.
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Metal sawhorse
Robust design. Chain with spring tensioning secures the trunk for cutting, max. load 100 kg.
Versions
Price- Metal sawhorse £96.50*
* Manufacturer's recommended retail price updated as of May 2022. The manufacturer's recommended retail prices are subject to change without notice.
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Chainsaw bag
Made from sturdy nylon. For safe storage and transport of all chainsaws with bar lengths up to 45 cm / 18". With small additional pocket for accessories.
Versions
Price- Carry bag for chainsaws £41.09*
* Manufacturer's recommended retail price updated as of May 2022. The manufacturer's recommended retail prices are subject to change without notice.
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2-in-1 EasyFile
Practical tool for quickly sharpening the teeth and depth gauge in a single action, significantly reducing chain maintenance time. The sturdy frame allows for a smooth filing action with highly accurate results. All the files are easily replaceable. For 1/4" P, 3/8" P, .325", 3/8" and .404" saw chains. Includes round and flat files.
To find out how to sharpen your chain and depth gauge with the EasyFile, click here.
Versions
Price- 2-in-1 file holder, 3/8" ø 5.2 mm £49.22*
* Manufacturer's recommended retail price updated as of May 2022. The manufacturer's recommended retail prices are subject to change without notice.
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BioPlus chain oil
Particularly eco-friendly with outstanding lubrication and adhesive properties. STIHL BioPlus is derived from plants and completely decomposes in the ground within a short space of time (tested according to OECD 301 B). It has been awarded the German 'Blue Angel' ecology mark and the European Eco-Label.
Versions
Price- BioPlus chain oil - 5 l £42.26*
* Manufacturer's recommended retail price updated as of May 2022. The manufacturer's recommended retail prices are subject to change without notice.
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The version(s) available in each country may differ from the above range and specifications; specific details may be subject to change without notice. Please ask your local STIHL Approved Dealer for further information.
Documents
Owners manuals and safety brochures
Languages | Date | Link |
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28/03/2022 |