FS 91 - $359.99 DSRP

Distributor Suggested Retail Price
FS 91

DSRP: $359.99


Reserve with STIHL Express for In-Store Pick Up

A professional bike-handle trimmer with simplified starting, improved air filtration and 30% longer run time than the FS 90.

The STIHL FS 91 trimmer delivers power and comfort for landscaping professionals. Its bike-handle design is great for mowing applications – and it’s more comfortable than ever thanks to 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, improv...Read More
Print Spec Sheets
FS 91 Specifications
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.
Model Features
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    Built in the USA
    Indicates products that are built in the United States from domestic and foreign parts and components.

    More Information

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    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.

    More Information

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    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.
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    Bike Handle
    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!
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    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.
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    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°.
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    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).
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    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.
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    Fully Lined Drive Shaft
    Provides smooth operation and less vibration.
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    High Tech Polymer Housing
    Housings are lightweight, withstand greater impact and are corrosion-resistant.
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    Protected Choke Lever/Knob
    Helps prevent damage.
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    Start/Run/Stop Controls on Handle
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    Throttle Trigger Interlock
    Must be depressed before the trigger can be activated.
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    Air Filter Cover
    Easily removed for fast and easy filter cleaning or replacement.
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    Protected or Enclosed Control Cables
    Eliminate dangling and loose wires.
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    Heavy-Duty Steel-On-Steel Clutch
    Centrifugal clutch is designed to reduce slippage.
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    Protected Spark Plug
    Protected yet easy to change.
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    Protected Spark Arrestor Muffler
    Has large baffles which reduce noise level and contains a screen designed to reduce the emission of sparks.
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    Upright Translucent Fuel Tank
    Allows operator to easily check fuel level before starting work. Upright position makes it easier to refill.
Standard Features
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    Common Features for Trimmers
    View the features common to many STIHL trimmers.

Important Information
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: Cancer and Reproductive Harm - www.p65warnings.ca.gov
ADVERTENCIA: Cáncer y Daño Reproductivo - www.p65warnings.ca.gov
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.
Click to view the STIHL Limited Warranty Time Periods
Optional Accessories
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    Gearbox Attachments
    Gearbox attachments are available for this model. View the interchangeable gearbox chart to find out which attachments work with this model.
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    Trimmer Heads & Blades
    Many trimmer heads and blades are available. Find out which ones to use with this model in this chart.  
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    Trimmer Line
    There's high-performance STIHL trimmer line for every operating condition. 
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    Protect yourself from flying debris while trimming. Check out our selection of deflectors and find the one that will help protect you.
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    Straps and Harnesses
    They distribute the load from your hands to your shoulders. They also help reduce operator fatigue and make it easier to use trimmers, brushcutters and clearing saws for extended periods.
We Also Suggest
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    HP Ultra 2-Cycle Engine Oil
    HP Ultra is a fully synthetic 2-cycle engine oil specially suited for high performance chainsaws and power tools. This oil has outstanding engine cleaning characteristics, plus “ultra” superior lubricating qualities in comparison to other 2-cycle engine oils. It is ideal for use in STIHL 4-MIX® engines. This oil is biodegradable, degrading by 80% in 21 days.

    •2.6 oz. bottle makes 1 gallon mix

    •5.2 oz. bottle makes 2 gallon mix

    •6.4 oz. bottle makes 2 1/2 gallon mix

    •12.8 oz. bottle makes 5 gallon mix

    STIHL recommends a mix of 50:1 high-quality 89 octane or higher unleaded gasoline to STIHL engine oil. This same mix ratio should be used during break-in.

For Your Safety
  • STIHL® Pro Mark™  Hearing Protector Zoom
    STIHL® Pro Mark™ Hearing Protector
    Padded stainless steel spring wire headband maintains constant pressure. Easy to adjust. Noise Reduction Rating (NRR): 29. Meets ANSI S3.19-1974 standard.

    Colors available: Camouflage, Orange and Grey

Are You Ready for a STIHL?

FS 91 is rated 4.3 out of 5 by 37.
Date published: 2018-07-03
Rated 5 out of 5 by from incredible power! Love my still fs-91 weedeater! No reason to buy anything else.
Date published: 2018-06-22
Rated 4 out of 5 by from Shame on Stihl and their Dealers PROS: So far, starts very easily, cuts great, have not tried the circular blade yet. I love it over any other weed eater I have used before. CONS:They hide it well on the fact that some of their products are now 4 cycle. Nothing in the specs online, or on the shelf's at dealers display area. I'm sure they tell the dealers not to disclose that their products are four stroke now. I should had seen the writing on the wall. Dealer selling points "low end torque, and EPA exhaust gas recycle, better gas consumption" I like my new fs 91 but I feel like I was tricked into thinking it was a 2 stroke. Now I have to worry about extra moving parts breaking down and higher maintenance due to having cam, push rods and valves.
Date published: 2018-06-06
Rated 5 out of 5 by from would not own anything eles to me there is no other and i would not buy any other
Date published: 2018-06-05
Rated 1 out of 5 by from Feed system I purchased a new trimmer in Mother's Day. It has been used to trim three time now. The first time line feed system worked for less the five minutes. After 30 minute I had stopped 5 times to refeed the line. Thought about returning that day but hardware was already close. Next time I used it. It was not more then five minutes again before the feed system stopped working again. To say the least I am very disappointed with the current Quality of this trimmer. Have a STIHL chain saw and blower both have been excellent products.
Date published: 2018-06-01
Rated 2 out of 5 by from Recommened as long as you don't need two stroke power My previous 4 stroke trimmer needed some extensive repairs, plus it never really had enough power. The dealer had this and another popular Japanese brand. I ended up buying the Stihl based on reputation and having heard how powerful some being used in my neighborhood were. I should've got the Japanese brand. No where is it mentioned that all the Stihl trimmers are now 4 stroke. I should've done more research, so my fault. It runs good, easy to start but doesn't really have much more power than the previous 4 stroke Japanese brand trimmer it replaced and about as much power as my 20 year old with many hours on it 2 stroke Japanese trimmer. Pretty disappointing. It bogs pretty easily in any thicker, wet grass, which is pretty much all the grass I use it on. It doesn't rev. Barely any increase from half throttle to full throttle. When the string is new and full length it struggles with just about any decent amount of grass. Only when the string gets worn down and inch or so is it able to cut decent without bogging down really bad. I think it's a little deceptive that Stihl doesn't come right out and say that they're using low power 4 stroke motors. Having to use premix on a 4 stroke kind of eliminates the only real benefit to it being a 4 stroke. It's just not worth the price. An inexpensive 2 stroke from from a big box store is going to have more power. And that's sad. At least I have a 4 year warranty.
Date published: 2018-05-23
Rated 5 out of 5 by from Optimisim Fulfilled Bought this to replace an older trimmer and because I wanted to use a chisel saw blade. The trimmer runs great, is powerful, easy to use, and handles well. I needed to adjust the strap mounting location (was not well balanced in the factory delivered location). The chisel saw is an awesome tool. Makes clearing small trees effortless. Stihl is everywhere, so service and parts are everywhere too if needed. I now own 2 Stihl chainsaws and a trimmer. Best tools I own.
Date published: 2018-05-16
Rated 4 out of 5 by from Trimmer has great features. It's nice to have a reliable trimmer and starts easy. The thing that sold me is the adjustable carburator that some manufacturers don't have, if neede down the road.
Date published: 2018-05-11
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