STIHL MS 251 Chainsaw

Top-range domestic chainsaw for regular firewood cutting

The STIHL MS 251 is a powerful 45.6 cm³ petrol chainsaw designed for regular firewood processing, rural property maintenance and appropriately sized tree work.

Its high-torque STIHL 2-MIX engine produces 2.2 kW / 3 hp, giving it more cutting capacity than smaller domestic saws while remaining considerably lighter than larger agricultural and professional forestry models.

The MS 251 is available from Masseys with either a 16″ / 40 cm or 18″ / 45 cm guide bar. Both versions use the same engine; the longer cutting attachment provides additional reach but does not increase engine power.

Every petrol chainsaw sold by Masseys is assembled, inspected, test-run and registered by our trained team before handover.

Browse our full range of STIHL petrol chainsaws or read Masseys’ STIHL chainsaw buying guide for further model-selection advice.

Key features of the STIHL MS 251

• 45.6 cm³ STIHL 2-MIX petrol engine
• 2.2 kW / 3 hp power output
• 4.8 kg powerhead weight without fuel, guide bar or chain
• Choice of 16″ / 40 cm or 18″ / 45 cm guide bar
• Current .325″ RM3 Pro cutting system
• 1.3 mm chain gauge
• Side-mounted chain tensioning
• STIHL long-life air-filter system
• HD2 fine-particle air filter
• Carburettor compensator
• STIHL Ematic chain-lubrication system
• STIHL anti-vibration system
• Tool-free fuel and chain-oil caps
• Automatic guide-bar and chain lubrication
• Suitable for frequent domestic and landowner use

Who should choose the STIHL MS 251?

The MS 251 is suited to homeowners, rural property owners and smallholders who regularly process firewood or need a capable petrol saw for land and tree maintenance.

It is particularly suitable for:

• Regular firewood processing
• Cross-cutting hardwood and softwood logs
• Clearing fallen branches
• Maintaining larger gardens and rural properties
• Timber construction and suitable woodworking tasks
• Felling appropriately sized small trees
• Users upgrading from a smaller domestic saw
• Customers who need more capacity without moving to a professional forestry chainsaw

It may be unnecessarily large for occasional light pruning, very small gardens or users who prioritise minimum weight above cutting output.

Choosing a 16-inch or 18-inch guide bar

The STIHL MS 251 is available with two guide-bar lengths.

Both versions use the same 45.6 cm³ engine and produce the same 2.2 kW / 3 hp output.

16″ / 40 cm guide bar

The 16-inch version is the recommended choice for many domestic and landowner users because it provides a useful balance of cutting capacity and manoeuvrability.

Choose the 16-inch version when:

• You primarily process ordinary domestic firewood
• Ease of handling is important
• You regularly work around branches or confined areas
• You do not need the extra reach of the longer bar

18″ / 45 cm guide bar

The 18-inch version provides additional guide-bar reach for larger logs, stems and branches.

Choose the 18-inch version when:

• You regularly encounter larger-diameter timber
• The additional reach is genuinely useful
• You are comfortable controlling a longer cutting attachment

A longer guide bar does not make the engine more powerful. It also adds weight and leverage at the front of the chainsaw, so the 16-inch version may remain the better choice where the additional reach is unnecessary.

45.6 cm³ STIHL 2-MIX engine

The MS 251 is powered by a 45.6 cm³ STIHL 2-MIX two-stroke engine producing 2.2 kW / 3 hp.

STIHL 2-MIX technology is designed to deliver strong cutting performance while reducing fuel consumption and exhaust emissions compared with older STIHL two-stroke engine designs of a similar power output.

The engine’s high-torque characteristics make the MS 251 particularly suitable for repeated firewood cutting and maintaining cutting speed through denser timber.

Current .325″ RM3 Pro cutting attachment

The current STIHL cutting system for the MS 251 uses a .325″ RM3 Pro saw chain with a 1.3 mm drive-link gauge.

The narrow-kerf RM3 Pro chain is designed to provide:

• Efficient cutting performance
• Reduced kerf width
• Low vibration
• Smooth cutting behaviour
• Efficient use of the available engine output

The correct replacement chain depends on the guide-bar length fitted to your machine.

Browse Masseys’ replacement chainsaw chain range or contact us with the model, bar length and markings stamped on the guide bar before ordering.

Side-mounted chain tensioning

The chain-tensioning screw is positioned through the side of the sprocket cover.

This gives protected access to the adjustment point without positioning the combination tool directly beside the sharp chain teeth.

Chain tension should be checked:

• Before each use
• After fitting a new chain
• During longer cutting sessions
• Whenever the chain no longer sits correctly against the underside of the guide bar

Switch off the engine, allow hot components to cool, release the chain brake and wear protective gloves before adjusting or handling the chain.

Long-life air-filter system

The MS 251 uses STIHL’s long-life air-filter system with pre-separation.

Centrifugal force separates larger particles from the cooling air before they reach the main filter. The HD2 filter then helps prevent finer dust from entering the engine.

This can extend cleaning intervals and maintain reliable engine performance during dusty firewood and property-maintenance work.

The filter must still be inspected, cleaned and replaced according to the operating instructions.

Carburettor compensator

The carburettor compensator helps maintain engine output, fuel consumption and exhaust quality as the air filter gradually becomes contaminated.

This allows the saw to continue working effectively for longer before a reduction in performance indicates that filter maintenance is required.

STIHL Ematic chain-lubrication system

The Ematic system combines the guide bar, Oilomatic saw chain and controlled-delivery oil pump to direct chain oil towards the areas where lubrication is required.

This can reduce unnecessary chain-oil consumption while maintaining suitable lubrication of the guide bar and chain.

Always check the chain-oil level and oil delivery before starting work. Running a chainsaw without adequate lubrication can rapidly damage the guide bar and chain.

STIHL anti-vibration system

Spring and buffer elements reduce the amount of engine and cutting vibration transmitted to the handles.

This can make the MS 251 more comfortable to control during appropriate firewood and property-maintenance work. It does not remove all vibration, so correct technique and regular breaks remain important.

Tool-free fuel and chain-oil caps

The fuel and chain-oil tanks use bayonet-style caps that can be opened and closed without a separate tool.

Check that both caps are correctly aligned and securely locked before starting the engine.

Fuel and chain-oil requirements

The MS 251 requires two separate fluids:

• A 50:1 mixture of petrol and approved two-stroke engine oil for the engine
• Dedicated chain oil for lubricating the guide bar and saw chain

For self-mixed fuel, use suitable fresh petrol with approved STIHL two-stroke engine oil at the correct ratio.

STIHL MotoMix ready-mixed fuel can also be used. It provides a consistent 50:1 mixture and a longer storage life than ordinary self-mixed petrol.

The cutting attachment requires separate STIHL chainsaw chain oil. Two-stroke engine oil must never be added to the chain-oil tank.

Fuel, two-stroke engine oil, chain oil and protective equipment are not included unless specifically listed as part of an offer.

STIHL MS 231 vs MS 251 vs MS 291

Model	Engine	Power	Weight	Best suited to
STIHL MS 231	42.6 cm³	2.0 kW	Approximately 4.8 kg	Regular firewood and general property maintenance
STIHL MS 251	45.6 cm³	2.2 kW	Approximately 4.8 kg	Heavier domestic firewood and regular land maintenance
STIHL MS 291	55.5 cm³	2.8 kW	Approximately 5.6 kg	Agricultural, smallholding and heavier landowner work

Choose the MS 231 where slightly lower output is sufficient.

Choose the MS 251 when you want more power without increasing the bare machine weight significantly.

Choose the MS 291 when the work regularly justifies its additional engine capacity and weight.

STIHL MS 251 or MS 251 C-BE?

The standard MS 251 and the MS 251 C-BE use the same engine and provide the same core cutting performance.

Feature	STIHL MS 251	STIHL MS 251 C-BE
Engine	45.6 cm³, 2.2 kW / 3 hp	45.6 cm³, 2.2 kW / 3 hp
Starting	Standard recoil starter	STIHL ErgoStart with manual fuel pump
Chain adjustment	Side-mounted screw using the combination tool	Tool-free STIHL Quick Chain Tensioning
Best suited to	Customers prioritising lower weight and purchase price	Customers prioritising easier starting and adjustment

Choose the standard MS 251 when you are comfortable with conventional recoil starting and tool-adjusted chain tensioning.

Choose the STIHL MS 251 C-BE when reduced starting effort and tool-free chain adjustment justify the additional cost and weight.

MS 251 or a professional chainsaw?

The MS 251 is STIHL’s top-range domestic petrol chainsaw. It is designed for demanding private use rather than continuous professional forestry.

Consider the professional STIHL MS 261 C-M when:

• The chainsaw will be used commercially
• Daily cutting performance is essential
• Professional power-to-weight performance is required
• Forestry durability and M-Tronic engine management are priorities

Technical specifications

Specification	Details
Model	STIHL MS 251
Product type	Top-range domestic petrol chainsaw
Engine	STIHL 2-MIX two-stroke petrol engine
Displacement	45.6 cm³
Power output	2.2 kW / 3 hp
Machine weight	4.8 kg without fuel, guide bar or saw chain
Power-to-weight ratio	Approximately 2.2 kg/kW
Guide-bar options	40 cm / 16″ or 45 cm / 18″
Chain pitch	.325″
Chain gauge	1.3 mm / .050″
Current compatible chain	STIHL RM3 Pro
Chain tensioning	Side mounted, adjusted with combination tool
Air filtration	Long-life system with pre-separation and HD2 filter
Fuel mixture	50:1 petrol and approved two-stroke engine oil, or STIHL MotoMix
Chain lubrication	Automatic STIHL Ematic system
Fuel and oil caps	Tool-free bayonet caps
Sound-pressure level	Approximately 103 dB(A)
Sound-power level	Approximately 113 dB(A)
Vibration level, left/right	Approximately 3.9 / 3.9 m/s²

What is included?

The standard package should include:

• STIHL MS 251 petrol chainsaw
• Selected 16″ or 18″ guide bar
• Matching STIHL saw chain
• Guide-bar scabbard
• Combination tool
• Operating and safety instructions

Fuel, two-stroke engine oil, chain oil and protective equipment are not included unless specifically stated.

Maintenance and service parts

Regular maintenance helps protect engine performance and cutting efficiency.

Routine checks should include:

• Chain tension and sharpness
• Guide-bar condition
• Chain-oil delivery
• Air-filter condition
• Fuel filter
• Spark plug
• Chain-brake operation
• Starter mechanism

The STIHL Service Kit 15 contains the air filter, fuel pickup body and spark plug required for routine MS 231 and MS 251 maintenance.

Chainsaw safety and protective equipment

The MS 251 is a powerful petrol chainsaw. Its domestic classification does not make it suitable for use without instruction or protective equipment.

Before use:

• Read the operating and safety manuals
• Understand the chain brake and kickback risks
• Receive suitable operating instruction
• Inspect the work area and timber
• Check chain tension and lubrication
• Keep other people and animals away

Suitable protective equipment should include:

• Chainsaw protective trousers
• Chainsaw boots or suitable cut-resistant footwear
• Eye or face protection
• Hearing protection
• Protective gloves
• A suitable helmet where falling material presents a risk

Browse Masseys’ chainsaw trousers and wider range of chainsaw accessories and PPE.

Never use a chainsaw from a ladder. Tree felling should only be attempted by a competent operator with a safe working area, an appropriate escape route and an understanding of the forces involved.

Warranty

The standard domestic warranty is two years, subject to STIHL’s current terms, correct use and appropriate maintenance.

Eligible domestic customers can extend the warranty from two to three years by purchasing five litres of STIHL MotoMix with the chainsaw and having the extension registered by the STIHL Approved Dealer at the point of purchase.

Why buy the STIHL MS 251 from Masseys?

Masseys is a STIHL Authorised Dealer based in Woodville, near Swadlincote.

Every petrol chainsaw sold by Masseys is assembled, inspected, test-run and registered by our trained team before handover.

Buying from Masseys gives you access to:

• Help choosing between the 16-inch and 18-inch versions
• Advice comparing the MS 231, MS 251 and MS 291
• Genuine UK STIHL chainsaws and cutting attachments
• Product setup and operating guidance
• Warranty registration and support
• Replacement guide bars and saw chains
• Fuel, two-stroke oil and chain oil
• Chain sharpening and workshop support
• Local collection and delivery options

Our garden machinery servicing and repairs workshop can assist with maintenance, repairs, chain sharpening and genuine STIHL replacement parts.

For help choosing the correct chainsaw or guide-bar length, please contact Masseys before ordering.

Frequently asked questions

What engine does the STIHL MS 251 have?

It has a 45.6 cm³ STIHL 2-MIX petrol engine producing 2.2 kW / 3 hp.

How much does the MS 251 weigh?

The powerhead weighs approximately 4.8 kg without fuel, guide bar or saw chain. The complete operating weight is higher once the cutting attachment, fuel and chain oil are added.

Is the MS 251 suitable for firewood?

Yes. Regular domestic firewood processing is one of its principal intended uses.

Should I choose the 16-inch or 18-inch version?

Choose the 16-inch version for easier handling and most domestic firewood work. Choose the 18-inch version when the additional guide-bar reach is genuinely useful. Both versions have the same engine and power output.

Is the 18-inch version more powerful?

No. Only the guide-bar and matching chain length change. The engine specification is identical.

What chain does the MS 251 use?

The current compatible cutting system uses a .325″ STIHL RM3 Pro chain with a 1.3 mm drive-link gauge. The required chain length depends on the guide bar fitted.

What is the difference between the MS 231 and MS 251?

The MS 251 has a larger 45.6 cm³ engine and 2.2 kW output, compared with 42.6 cm³ and 2.0 kW for the MS 231. Their bare machine weights are similar.

What is the difference between the MS 251 and MS 251 C-BE?

They use the same engine. The MS 251 C-BE adds STIHL ErgoStart, a manual fuel pump and tool-free Quick Chain Tensioning.

Is the MS 251 suitable for a first-time user?

It can be used by a properly instructed domestic operator, but its power and cutting capacity make it better suited to regular chainsaw work than occasional lightweight use. Suitable PPE and an understanding of safe chainsaw operation are essential.

What fuel does it use?

It uses a 50:1 mixture of suitable petrol and approved two-stroke engine oil. STIHL MotoMix ready-mixed fuel can also be used.

Does it require separate chain oil?

Yes. Dedicated chain oil must be added to the chain-oil tank to lubricate the guide bar and chain.

Does it include fuel or oil?

Fuel, two-stroke oil and chain oil are not normally included unless expressly listed as part of the offer.

Can it fell trees?

It can be used for appropriately sized tree work by a competent operator. Larger trees, difficult conditions and commercial felling require suitable training, planning and potentially a professional forestry chainsaw.

Can Masseys service and sharpen it?

Yes. Masseys provides chainsaw servicing, repairs, genuine replacement parts and chain sharpening through its on-site garden-machinery workshop.