Stihl MS 661 C-M Petrol Chainsaw (91.1cc)

Stihl MS 661 Petrol Chainsaw
Professional High-Performance Chainsaw for Forestry & Large Timber
The Stihl MS 661 is a legendary professional-grade petrol chainsaw designed for the most demanding forestry, arborist and large-scale timber applications. Built for power, durability and precision, the MS 661 delivers exceptional cutting performance when working with large-diameter hardwood and softwood.
As one of Stihl’s flagship high-displacement chainsaws, the MS 661 combines advanced engine technology with robust construction to ensure reliable performance in extreme working conditions. Whether you’re felling large trees, milling timber or carrying out heavy forestry operations, this machine is engineered for serious professional use.

Technical Data

Recommended bar length cm/inch	36″
Displacement cm³	91.1
Power output kW/bhp	5.4/7.3
Weight kg 1)	7.4
Power-to-weight ratio kg/kW	1.4
Sound pressure level dB(A) 2)	105
Sound power level dB(A) 2)	118
Vibration values left/right m/s² 3)	5.5/5.5
STIHL Oilomatic saw chain pitch/type	3/8″ RS

Consumables + Accessories for this Chainsaw

Bars + Chains:

28″

• Stihl 28″ Rollomatic ES Light 3/8″ .063″ (1.6mm) Chainsaw Guide Bar 3003-000-2038
• Stihl 28″ Rapid Super (RS) 3/8″ .063″ (1.6mm) Chainsaw Chain 3621-000-0091 – 91 Drive Links

30″

• Stihl 30″ Rollomatic ES 3/8″ .063″ (1.6mm) Chainsaw Guide Bar 3003-000-6041
• Stihl 30″ Rapid Super (RS) 3/8″ .063″ (1.6mm) Chainsaw Chain 3621-000-0098 – 98 Drive Links

36″

• Stihl 36″ Rollomatic ES 3/8″ .063″ (1.6mm) Chainsaw Guide Bar 3003-000-6053
• Stihl 36″ Rapid Super (RS) 3/8″ .063″ (1.6mm) Chainsaw Chain 3621-000-0114 – 114 Drive Links

Service Kit:

• Stihl Service Kit 16 (for MS 661)

Sharpening:

• Stihl 2-in-1 EasyFile (Chainsaw Chain File) for 3/8″ Chain – 5.2mm 5605-750-4305
• Stihl Chain Sharpening/Filing File Kit for 3/8″ Chain 5605-007-1029

Engine Oil (Good, Better, Best):

• Stihl HP 2-Stroke Engine Oil: 100ml, 1 Litre, 5 Litres
• Stihl HP Super 2-Stroke Engine Oil: 100ml, 1 Litre, 5 Litres
• Stihl HP Ultra 2-Stroke Engine Oil: 100ml, 1 Litre, 5 Litres

Chain Oil (Good, Better, Best):

• Stihl ForestPlus: 1 Litre, 5 Litres
• Stihl SynthPlus: 1 Litre, 5 Litres
• Stihl BioPlus: 1 Litre, 5 Litres

Accessories:

• Stihl 2-Stroke Fuel Mixing Bottle
• Stihl Combi Can: Orange, Transparent
• Stihl Wooden Sawhorse

Cleaning + Care:

• Stihl MS Care Clean Kit (Chainsaw Cleaning Kit)
• Stihl MS Care Clean Kit PLUS (Chainsaw Cleaning Kit)
• Stihl VarioClean Special Cleaner 500ml
• Stihl Superclean Resin Solvent 50ml, 300ml
• Stihl Multispray 400ml

Key Features of the Stihl MS 661
High-Power 2-Stroke Engine – Exceptional performance for heavy-duty cutting
Large Displacement (90cc Class) – Designed for felling and processing large timber
Advanced Engine Technology – Efficient fuel use and reduced emissions
HD2 Air Filter System – Long service intervals in dusty conditions
Anti-Vibration System – Reduces fatigue during prolonged operation
Heavy-Duty Crankcase & Components – Built for professional forestry work
Compatible with Long Guide Bars – Suitable for large-diameter cutting applications
The MS 661 is built to deliver maximum torque and cutting speed while maintaining operator control and durability in tough environments.
Ideal Applications
Professional forestry work
Felling large trees
Timber processing
Sawmilling applications
Heavy-duty arborist operations
This is a chainsaw designed for experienced professional users who require uncompromising performance.
Frequently Asked Questions – Stihl MS 661
Is the Stihl MS 661 suitable for domestic use?
The MS 661 is a professional forestry chainsaw and is generally recommended for experienced users and commercial applications rather than occasional domestic use.
What engine size is the MS 661?
The Stihl MS 661 is in the 90cc class, offering high power output suitable for large timber and demanding tasks.
What bar length can the MS 661 run?
The MS 661 can be fitted with a range of guide bar lengths, typically from around 20″ up to 36″ (model specification dependent). Always ensure the correct bar and chain combination is used.
Does the MS 661 have anti-vibration features?
Yes. It includes a professional-grade anti-vibration system to reduce operator fatigue during long working hours.
What fuel does it require?
The MS 661 uses a 2-stroke petrol and oil mix, following Stihl’s recommended fuel ratio.
What maintenance is required?
Routine maintenance includes:
Checking and cleaning the air filter
Inspecting the spark plug
Maintaining correct chain tension
Regular chain sharpening
Using fresh, correctly mixed fuel
Professional servicing is recommended for optimal longevity.
Does it come with warranty?
Yes. When purchased from Radmore & Tucker as an authorised dealer, the MS 661 is supplied with manufacturer warranty (terms vary depending on domestic or professional use).
Why Buy the Stihl MS 661 from Radmore & Tucker?
Authorised Stihl Dealer
Expert advice for professional machinery
Genuine Stihl parts and accessories
After-sales support and servicing
Trusted UK family-run business
For serious forestry performance and uncompromising cutting power, the Stihl MS 661 remains one of the most trusted professional chainsaws available — supplied by Radmore & Tucker.