Overview
STIHL engine technology means low fuel consumption, longer run times, and reduced exhaust emissions in this high-powered chainsaw. The MS 391 features STIHL engine technology that adds fuel efficiency while reducing exhaust emissions, as compared to other chainsaw models. Though equal in weight, the MS 391 is more powerful than the MS 311. Add to that an optimal power-to-weight ratio and you have a chainsaw thats cut out for the big jobs in field, farm, and ranch. Felling trees, cutting firewood, and cleanup after the storm just got a whole lot easier with the rugged MS 391.
Features
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.
Bumper Spikes
These spikes prevent pull-in and provide better control, making cutting easier.
High-Tech Polymer Housings
Housings are lightweight, withstand greater impact, and are corrosion-resistant.
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.
Master Control Lever™
The Master Control Lever™ is an easy to use single lever, operating the choke, starting throttle lock, and on-off switch. The operator must pull the throttle trigger before moving the Master Control Lever™ to the choke position.
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.
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.
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.
Throttle Trigger Lockout
This safety feature must be depressed before the trigger can be activated.
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.
Specifications
| Bar length | 18 " |
| Device weight without refuelling | 13.8 lb |
| System weight without refuelling | 7.59 kg |
| Displacement | 3.9 cu-in |
| Device length with bumper spike | 458 mm |
| Power | 3.30 kW |
| Engine power | 4.50 HP |
| Power-to-weight ratio | 1.90 kg/kW |
| Groove width | 50 " |
| Saw chain pitch | 3/8" |
