A professional bike-handle trimmer with simplified starting, improved air filtration and 30% longer run time than the FS 90.
If you’re a landscaping professional who uses their trimmer for mowing applications, grab the powerful STIHL FS 91 trimmer. Its bike-handle design adds greater comfort and leverage, thanks to its redesigned rubberized grips. The trimmer also features one touch stop and a simplified starting procedure enabled by the semi-automatic choke lever. Its low-emission engine is paired with a larger fuel tank, delivering 30% longer run times when compared to the FS 90. The engine also includes improved air filtration and STIHL exclusive IntelliCarb™ technology for maximum RPM. And when the terrain gets tough, this trimmer’s solid steel drive shaft accepts a wide range of heavy-duty cutting heads, including metal blades, for maximum versatility.
|FS 91 Specifications - Professional Use|
|DISPLACEMENT||28.4 cc (1.73 cu. in.)|
|ENGINE POWER||0.95 kW (1.27 bhp)|
|WEIGHT*||5.8 kg (12.8 lbs.)*|
|FUEL CAPACITY||710 cc (24.0 oz.)|
|*Without deflector and cutting attachment.|
WARNING! Improper use of any trimmer/brushcutter can cause serious or fatal injury. Read, understand and follow all safety instructions in your instruction manual. To reduce the risk of injury from blade contact, circular saw blades may be used on FS brushcutters that have a limitstop, a bicycle handle and double shoulder harness and not on FS brushcutters with a "J" handle or loop handle. Other rigid blades may be used on FS brushcutters having a bicycle handle, a "J" handle or a loop handle equipped with a barrier bar. To reduce the risk of eye injury always wear proper eye protection. Always use the appropriate deflector for the type of cutting attachment, as explained in your instruction manual.
Note: STIHL engine products with the Caring for Nature logo are cleaner than EPA Standards for exhaust emissions.
Note: STIHL recommends use of fuel with no more than 10% Ethanol content. Using fuel with greater than 10% Ethanol content may cause damage to your equipment and may void your STIHL warranty. Learn More…
WARNING! Improper use of any power tool may cause serious
or fatal injury. Read, understand and follow carefully the operating
and safety instructions in your instruction manual before using such products.
STIHL products sold through U.S. STIHL Dealers are for distribution in the United States only.
Built in the USA
Indicates products that are built in the United States from domestic and foreign parts and components.
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.
Shoulder Strap / Carrying System
Using a shoulder strap or carrying system helps distribute the weight of the equipment for increased operator comfort and improved maneuverability.
When used in conjunction with a harness, the bike handle allows the machine to be easily guided, enabling a smooth horizontal mowing action to cover large areas quickly and efficiently. With soft grips for increased comfort, the bike handle provides greater control and helps reduce operator fatigue.
See it in action!
Multi-Function Control Handle
Having easy access to all of the controls on one comfortable handle makes it easy to complete tasks so the operator’s hand never has to leave the handle.
Tool-Free Handle Adjustment
The central wing nut enables easy adjustment without the use of tools. For transportation and space-saving storage, the handle can be rotated 90°.
Cutting Heads & Blades Selection Chart
Need help selecting a cutting head or blade for your STIHL trimmer or brushcutter?
Click here to view the Cutting Heads & Blades Selection Chart (PDF Format).
Purge Pump Primer
By pressing the bulb, this small fuel pump delivers fuel to the carburetor, reducing the number of starting pulls needed after an extended break between uses.
Fully Lined Drive Shaft
Provides smooth operation and less vibration.
High Tech Polymer Housing
Housings are lightweight, withstand greater impact and are corrosion-resistant.
Protected Choke Lever/Knob
Helps prevent damage.
Start/Run/Stop Controls on Handle
Throttle Trigger Interlock
Must be depressed before the trigger can be activated.
Air Filter Cover
Easily removed for fast and easy filter cleaning or replacement.
Protected or Enclosed Control Cables
Eliminate dangling and loose wires.
Heavy-Duty Steel-On-Steel Clutch
Centrifugal clutch is designed to reduce slippage.
Protected Spark Plug
Protected yet easy to change.
Protected Spark Arrestor Muffler
Has large baffles which reduce noise level and contains a screen designed to reduce the emission of sparks.
Upright Translucent Fuel Tank
Allows operator to easily check fuel level before starting work. Upright position makes it easier to refill.
Common Features for Trimmers
View the features common to many STIHL trimmers.
You Will Also Need
No matter how you slice it (or trim it or shred it), there’s no better protection for your high performance 2-stroke engine than STIHL HP Ultra. This 2-cycle engine oil has outstanding engine cleaning characteristics, plus “ultra” lubricating qualities that are superior to other 2-cycle engine oils. This fully synthetic oil is also highly biodegradable, degrading by 80% in 21 days. We’re so confident this oil will protect your engine, we’ll double your STIHL limited warranty* when you use it. It’s that good.
*Double your warranty when you purchase either STIHL HP Ultra Oil (six-pack) or STIHL MotoMix® Patented Premixed Fuel (one gallon minimum) with your STIHL product purchase. Double limited warranty protection applies to STIHL gasoline-powered products purchased and registered for personal non-income producing, family and household purposes only. Other restrictions apply. See dealer for details.
No-Spill® fuel containers advance convenience and quality in gasoline-can design by reducing emissions of hydrocarbons from evaporation, permeation and spillage. This helps protect the environment as well as saves you on fuel costs due to waste. Each container is molded from fluorinated, high molecular weight material for low permeation. The thumb-button flow control allows filling even smaller-sized tanks reducing the risk of spilling and is designed to stop the flow automatically when the tank becomes full to prevent overflowing. Built on a wide and stable base for less likelihood of upsets and equipped with child-resistant closures, all No-Spill® containers comply with both EPA and CARB requirements. With 1¼-gallon, 2 ½-gallon and 5-gallon sizes available, you’re sure to find one that fits your needs.
For Your Safety
Heavy machinery doesn’t have anything interesting to say – block out that noise with our most noise-reducing hearing protection. These top-quality Hearing Protectors feature padded stainless steel spring-wire headbands maintain constant pressure. So no sliding around and letting in unwanted sound waves. They’re also easy to adjust. Set a comfortable fit and get to work in peace.
Meets ANSI S3.19-1974 standard. Noise Reduction Rating (NRR) of 29 dB(A).
Available color: Orange
When you need professional-grade protection for your hands, STIHL Outdoor PRO Gloves deliver it all. High-quality synthetic leather offers comfort and durability. That durability is enhanced further by TPR (thermoplastic rubber)-padded knuckle and finger areas. The gloves are lightweight and offer high dexterity. The material is also breathable for all-day comfort. They’re the PRO way to go.
They’re comfortable. They’re functional. They’re from STIHL. Featuring a hollowed-out frame, our Two-Tone Work Glasses are as lightweight as they are stylish. Designed with flexible rubber tips and nose pads, these glasses help you get the job done with greater comfort and fewer slips. Meeting ANSI standard Z87.1+ and offering 99% UV protection, the STIHL Two-Tone Work Glasses will have you covered in more ways than one.
STIHL Trimmers & Edgers, the Right Tools for the Job - Video
How to Wind a STIHL Trimmer Head - Video
Cutting Heads & Blades Selection Chart (PDF)
FS 91 Instruction Manual (PDF)
Download Instructions on How to Rewind Your Trimmer Head (PDF)
Product Safety Manual (PDF)
STIHL Limited Warranty