{"product_id":"stihl-ms661-c-m-high-performance-petrol-chainsaw","title":"MS 661 C-M Petrol Chainsaw","description":"\u003ch1\u003eSTIHL MS 661 C-M Petrol Chainsaw – Magnum Power for Professional Forestry\u003c\/h1\u003e\n\u003cdiv style=\"margin:24px 0; padding:26px; border:1px solid #e5e7eb; border-left:3px solid #f47a20; border-radius:20px; background:#f7f7f7; font-family:-apple-system,BlinkMacSystemFont,'Segoe UI',Roboto,Helvetica,Arial,sans-serif;\"\u003e\n\u003cdiv style=\"display:flex; align-items:center; margin-bottom:8px;\"\u003e\n\u003cspan style=\"display:inline-block; width:6px; height:6px; border-radius:50%; background:#f47a20; margin-right:10px;\"\u003e\u003c\/span\u003e\u003ch3 style=\"margin:0; font-size:18px; font-weight:600; color:#1c1f27; letter-spacing:-0.01em;\"\u003eFree Spare Chain Available\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cp style=\"margin:0 0 12px; font-size:14px; line-height:1.5; color:#f47a20; font-weight:700;\"\u003eWorth £20–£40 depending on model\u003c\/p\u003e\n\u003cp style=\"margin:0 0 16px; font-size:14px; line-height:1.8; color:#4b5563;\"\u003eWhen you add this STIHL chainsaw to your cart, your free matching chain will appear automatically. Simply click \u003cstrong\u003e\"Add Free Item\"\u003c\/strong\u003e in the cart to include it with your order.\u003c\/p\u003e\n\u003cul style=\"margin:0 0 16px 18px; padding:0; font-size:13.5px; line-height:1.85; color:#4b5563;\"\u003e\n\u003cli\u003eMatching chain for this model\u003c\/li\u003e\n\u003cli\u003eIdeal for quick swaps on the job\u003c\/li\u003e\n\u003cli\u003eHelps reduce downtime\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003chr style=\"border:none; border-top:1px solid #e5e7eb; margin:16px 0;\"\u003e\n\u003cp style=\"margin:0; font-size:12.5px; line-height:1.7; color:#6b7280;\"\u003eYour free chain will appear in the cart — just click \u003cstrong\u003e\"Add Free Item\"\u003c\/strong\u003e before checkout.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cp\u003eThe \u003cstrong\u003eSTIHL MS 661 C-M\u003c\/strong\u003e is one of STIHL's most powerful production chainsaws, built for large-scale felling, heavy timber processing and demanding commercial forestry operations. A 91.1cc 2-MIX engine produces 5.4 kW (7.3 hp) at 7.5 kg without bar and chain, with M-Tronic electronic engine management delivering consistent power across all conditions. Bar lengths from 50–90 cm (20–36\") make the MS 661 the right choice for large-diameter timber where the MS 462 or MS 500i reach their limits. In stock at Gustharts as an authorised STIHL dealer, with free UK delivery over £75.\u003c\/p\u003e\n\u003ch2\u003eKey Features\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e91.1cc 2-MIX Engine, 5.4 kW \/ 7.3 hp\u003c\/strong\u003e – Formidable cutting performance with notable reductions in fuel use and emissions versus conventional 2-stroke design.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSTIHL M-Tronic Engine Management\u003c\/strong\u003e – Automatically adjusts timing and fuel mix for peak performance across temperature, altitude and fuel quality variations.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e7.5 kg Without Bar and Chain\u003c\/strong\u003e – Substantial but manageable for a 91cc professional saw; power-to-weight ratio of 1.4 kg\/kW.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBar Compatibility: 50–90 cm (20–36\")\u003c\/strong\u003e – Covers large-diameter felling through to timber processing with appropriate bar selection.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHD2 Washable Air Filter\u003c\/strong\u003e – Long-life pre-separation filter for dusty forestry environments with reduced maintenance frequency.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEmatic Oil Lubrication System\u003c\/strong\u003e – Reduces bar oil consumption by up to 50% with precision demand-led delivery.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eElastoStart and Manual Decompression Valve\u003c\/strong\u003e – Reduced starting effort and starter protection.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAnti-Vibration System\u003c\/strong\u003e – Advanced vibration dampening for extended shifts on large timber.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSide-Mounted Chain Tensioner and Tool-Free Caps\u003c\/strong\u003e – Fast chain adjustments and refuelling without tools.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eTechnical Specifications\u003c\/h2\u003e\n\u003ctable style=\"width:100%; border-collapse:collapse; border:1px solid #e5e5e5; border-radius:20px; overflow:hidden; font-size:14px; line-height:1.5; color:#111;\"\u003e\n\u003ccolgroup\u003e\n\u003ccol style=\"width:42%\"\u003e\n\u003ccol style=\"width:58%\"\u003e\n\u003c\/colgroup\u003e\n\u003ctr\u003e\n\u003cth style=\"background:#f8f8f8; font-weight:600; text-align:left; padding:18px 20px; border-bottom:1px solid #e5e5e5;\"\u003eSpecification\u003c\/th\u003e\n\u003cth style=\"background:#f8f8f8; font-weight:600; text-align:left; padding:18px 20px; border-bottom:1px solid #e5e5e5;\"\u003eDetails\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding:18px 20px; border-bottom:1px solid #e5e5e5;\"\u003eDisplacement\u003c\/td\u003e\n\u003ctd style=\"padding:18px 20px; border-bottom:1px solid #e5e5e5;\"\u003e91.1cc\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding:18px 20px; border-bottom:1px solid #e5e5e5;\"\u003ePower Output\u003c\/td\u003e\n\u003ctd style=\"padding:18px 20px; border-bottom:1px solid #e5e5e5;\"\u003e5.4 kW (7.3 hp)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding:18px 20px; border-bottom:1px solid #e5e5e5;\"\u003eWeight (without bar and chain)\u003c\/td\u003e\n\u003ctd style=\"padding:18px 20px; border-bottom:1px solid #e5e5e5;\"\u003e7.5 kg\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding:18px 20px; border-bottom:1px solid #e5e5e5;\"\u003ePower-to-Weight Ratio\u003c\/td\u003e\n\u003ctd style=\"padding:18px 20px; border-bottom:1px solid #e5e5e5;\"\u003e1.4 kg\/kW\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding:18px 20px; border-bottom:1px solid #e5e5e5;\"\u003eRecommended Bar Length\u003c\/td\u003e\n\u003ctd style=\"padding:18px 20px; border-bottom:1px solid #e5e5e5;\"\u003e50–90 cm (20–36\")\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding:18px 20px; border-bottom:1px solid #e5e5e5;\"\u003eChain Type\u003c\/td\u003e\n\u003ctd style=\"padding:18px 20px; border-bottom:1px solid #e5e5e5;\"\u003e⅜\" RS\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding:18px 20px; border-bottom:1px solid #e5e5e5;\"\u003eSound Pressure \/ Power Levels\u003c\/td\u003e\n\u003ctd style=\"padding:18px 20px; border-bottom:1px solid #e5e5e5;\"\u003e105 \/ 115 dB(A)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding:18px 20px;\"\u003eVibration (L\/R)\u003c\/td\u003e\n\u003ctd style=\"padding:18px 20px;\"\u003e6.9 \/ 5.6 m\/s²\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\n\u003ch2\u003eWhy Choose the STIHL MS 661 C-M?\u003c\/h2\u003e\n\u003cp\u003eThe MS 661 C-M occupies the position between the MS 500i and the MS 881 Magnum in the STIHL forestry range. At 91.1cc it delivers substantially more torque than the MS 500i for large-diameter felling without reaching the extreme weight of the MS 881 at 9.9 kg. For contractors working old-growth timber, large softwoods or hardwoods where bar lengths above 60 cm are regularly needed, the MS 661 C-M is the practical choice. M-Tronic delivers reliable performance without carburettor adjustment even at altitude or in cold conditions.\u003c\/p\u003e\n\u003ch2\u003eComplete Your Kit\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003ca href=\"\/en-us\/collections\/chainsaw-chains\" style=\"color:#1c1f27;\"\u003eReplacement Chainsaw Chains\u003c\/a\u003e – ⅜\" RS chains compatible with the MS 661 C-M\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"\/en-us\/collections\/stihl-chainsaw-guide-bars\" style=\"color:#1c1f27;\"\u003eChainsaw Guide Bars\u003c\/a\u003e – 50–90 cm bars for this model\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"\/en-us\/collections\/fuel-oil\" style=\"color:#1c1f27;\"\u003e2-Stroke Oil and Fuel\u003c\/a\u003e – STIHL HP Ultra and MotoMix for 2-MIX engines\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"\/en-us\/collections\/filing-kits-guides-sharpening\" style=\"color:#1c1f27;\"\u003eChain Sharpening Tools\u003c\/a\u003e – filing kits and bench sharpeners for ⅜\" RS chain\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"\/en-us\/collections\/chainsaw-clothing-ppe\" style=\"color:#1c1f27;\"\u003eForestry PPE\u003c\/a\u003e – chainsaw trousers, helmets, gloves and boots for compliant felling work\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eFAQs\u003c\/h2\u003e\n\u003ch3\u003eHow does the MS 661 C-M compare to the MS 500i?\u003c\/h3\u003e\n\u003cp\u003eThe MS 661 C-M is larger at 91.1cc versus 79.2cc, producing 5.4 kW versus 5.0 kW, and weighs 7.5 kg versus 6.3 kg. The MS 661 is the better choice for consistently large-diameter timber; the MS 500i offers better weight and fuel injection technology for mixed forestry work.\u003c\/p\u003e\n\u003ch3\u003eWhat bar lengths does the MS 661 C-M accept?\u003c\/h3\u003e\n\u003cp\u003eSTIHL recommend 50–90 cm (20–36\") guide bars with ⅜\" RS chain. Gustharts stocks compatible bars and chains.\u003c\/p\u003e\n\u003ch3\u003eIs the MS 661 C-M suitable for chainsaw milling?\u003c\/h3\u003e\n\u003cp\u003eYes — with bar options up to 90 cm and strong sustained torque it is well suited to Alaskan mill and portable sawmill setups for large log processing.\u003c\/p\u003e\n\u003ch3\u003eDoes the MS 661 C-M have a heated handle option?\u003c\/h3\u003e\n\u003cp\u003eNo — the MS 661 C-M does not have a heated handle variant. For cold-climate forestry work with heated handles, the MS 261 C-M VW and MS 500i W are the available STIHL options.\u003c\/p\u003e\n\u003ch3\u003eHow does M-Tronic work on the MS 661 C-M?\u003c\/h3\u003e\n\u003cp\u003eM-Tronic continuously monitors and adjusts ignition timing and fuel delivery electronically, removing the need for manual carburettor tuning in the field across varying temperatures, altitudes and fuel conditions.\u003c\/p\u003e","brand":"Stihl","offers":[{"title":"20\"","offer_id":55311730770294,"sku":"MS-1144 200 0006","price":1681.0,"currency_code":"USD","in_stock":true},{"title":"25\"","offer_id":55311730803062,"sku":"MS-1144 200 0009","price":1694.0,"currency_code":"USD","in_stock":true},{"title":"28\"","offer_id":45717607121140,"sku":"MS-1144 200 0319","price":1759.0,"currency_code":"USD","in_stock":true},{"title":"30\"","offer_id":55311730835830,"sku":"MS-1144 200 0013","price":1739.0,"currency_code":"USD","in_stock":true},{"title":"36\"","offer_id":45717607153908,"sku":"MS-1144 200 0324","price":1788.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0690\/6603\/1348\/files\/1_b6eeb601-364d-4e45-a09a-1937f6e89fac.png?v=1764847925","url":"https:\/\/www.gustharts.com\/en-us\/products\/stihl-ms661-c-m-high-performance-petrol-chainsaw","provider":"Gustharts","version":"1.0","type":"link"}