Overview
With an advanced low-emission engine technology, the STIHL MS 391 mid-range chainsaw improves fuel efficiency by up to 20% compared to previous models. The new air filtration system requires fewer filter changes, allowing for longer run times. Improved fuel efficiency and fewer filter changes save you time and money.
Features
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.
Bumper Spikes
These spikes prevent pull-in and provide better control, making cutting easier.
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.
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.
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.
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.
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.
Throttle Trigger Lockout
This safety feature must be depressed before the trigger can be activated.
High-Tech Polymer Housings
Housings are lightweight, withstand greater impact, and are corrosion-resistant.
Specifications
| POWER SOURCE | Gas |
| POWERHEAD WEIGHT | 13.67 lbs. |
| GUIDE BAR LENGTH (Recommended) | 20 in. |
| OILOMATIC® CHAIN | 3/8" RS3 |
| CHAIN OIL CAPACITY | 11.8 oz. |
| ENGINE POWER | 4.4 bhp |
| FUEL CAPACITY | 20.3 oz. |
| DISPLACEMENT | 64.1 cc |
| INTENDED USE | Farm/Ranch |