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FS 91 R

FS 91 R
A professional trimmer packed with features for simplified and convenient trimming.

Product Description

Fulfilling the demanding landscaper’s trimming needs, the STIHL FS 91 R trimmer is the well-rounded choice for professionals. It features a low-emission engine and large fuel tank which provides 30% longer run times than the previous model. With its rubberized loop handle, this straight-shaft trimmer delivers a comfortable grip of product, the maneuverability needed to navigate obstacles and the power to cut them down. The FS 91 R trimmer also has a simplified three-step start procedure that saves users time, and a superior air filter benefitting you in the long run.

Model Features

  • 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.

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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

  • 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.
  • Protected Spark Arrestor Muffler
    Has large baffles which reduce noise level and contains a screen designed to reduce the emission of sparks.
  • Heavy-Duty Steel-On-Steel Clutch
    Centrifugal clutch is designed to reduce slippage.
  • Protected or Enclosed Control Cables
    Eliminate dangling and loose wires.
  • Air Filter Cover
    Easily removed for fast and easy filter cleaning or replacement.
  • Throttle Trigger Interlock
    Must be depressed before the trigger can be activated.
  • Start/Run/Stop Controls on Handle
  • Protected Choke Lever/Knob
    Helps prevent damage.
  • High Tech Polymer Housing
    Housings are lightweight, withstand greater impact and are corrosion-resistant.
  • Fully Lined Drive Shaft
    Provides smooth operation and less vibration.
  • Adjustable Front Handle
    Adjusts for comfort.


28.4 cc (1.73 cu. in.)
0.95 kW (1.27 bhp)
5.5 kg (12.1 lbs.)*
710 cc (24.0 oz.)
*Without deflector and cutting attachment.

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! 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.


FS 91 R is rated 4.4 out of 5 by 55.
Rated 5 out of 5 by from AWESOME! I have two of these in my lawn care setup and they are the best trimmers on the market!
Date published: 2017-12-08
Rated 2 out of 5 by from FS 91 I purchased this product from Ace hardware. My other trimmer was stolen. I wanted the previous model just like the one I purchased 6 months prior. I was given the FS 91 model because the 90 was no longer available. Big mistake buying the FS 91. It’s a pain trying to turn it on. I still don’t fully understand how to turn it on. The 90 model was so simple to turn and easy to maneuver. The price was also overrated. The FS 91 quality is like a residential home owner product. It should not be categorized as a pro product. I wish I can get my money back...
Date published: 2017-11-29
Rated 5 out of 5 by from best value-for-money trimmer on the market starts very quickly, third pull for me. surprisingly light, considering its size. very powerful. love the rubber grips, too. It is a very comfortable trimmer, great for prolonged use. Also, I can cut around 15 yards on one tank of gas. my only complaints are the lack of a detachable shaft, and it can be difficult to disassemble the head to restring it. I have to use a flathead screwdriver. I have used many trimmers, this is the best one. very good trimmer for the money.
Date published: 2017-11-07
Rated 5 out of 5 by from Perfect size I bought this trimmer to clear out shooting lanes. I bought the 3 blade cutter for clearing saplings and briars. The trimmer has plenty of power and not real heavy. Super fuel efficient.
Date published: 2017-11-01
Rated 5 out of 5 by from This product is dependable and powerful This trimmer started right up after the cold winter months. Ran all spring and summer with no issues. LOVE all Stihl products!!
Date published: 2017-10-28
Rated 5 out of 5 by from FS 91R works well So far it has done all it is advertised to do. Starts pretty quickly, runs like a Stihl should, and is hassle free.
Date published: 2017-10-25
Rated 2 out of 5 by from Low on power and high on gas consumption This is my first Stihl product and I was excited to buy it. I purchased a Stihl FS91R a week and a half ago. I used it once. I did a lot of research and was going to get this or the Komi 91. After talking to the dealer I went with this and ordered the edging head to swap too.It starts up great and idles very nice. After that it loses it's glamour. When trimming it doesn't take much to slow it down, and anything thicker than a blade of grass it is unable to cut, Instead the line wraps around the weed stalk, or I have to take smaller bites through the grass. When at full throttle it sounds like the engine is starving and doesn't have a nice consistent engine purr. I also noticed that when going from idle to rev it to cut I can hear a metal clunk like the clutch is engaging. This should be audible. I only ran one full tank of gas in this, and was only able to trim my yard and my neighbor's when it ran out of gas. I am disappointed because I expected so much more from the Stihl product. I finally retired my old MAC trimmer after 23 years. it had much more power and ran great. It effortlessly mowed down grass, weeks, and small trees with little effort and only a weed trimmer line (no special brushcutter head). With my old machine I was also able to trim for about a month or more before having to refuel. Maybe I should just return the Stihl and buy a new ZAMA carburetor for my MAC and put it back to work. For a brand new machine this Stihl should not have to go back for work right from the start. This is not a satisfactory machine. I expected more especially since I went a step up from homeowner to the professional grade. Would I ever be losing business if owned a landscaping company and had to rely on this? Yes I would.
Date published: 2017-10-20
Rated 5 out of 5 by from Swappable Head Units? YES PLEASE! I went to a Popps store in a neighboring city that came highly recommended. I went in the first time to just ask some questions about the Kombi system. He said that they don’t normally carry the Kombi in store cause you can change the head stock on a normal trimmer unit for whatever your needs may be. Blew my mind. Went in a second time to buy the unit. Ended up going with the 91R, the edger unit, 6pk of oil (cause they double your warranty from 2 to 4. No brainer their!) and a new gas tank. Starting fresh! I just recently started taking care of my churches property which is actually 4 in one. And this unit has come in very handy and VERY easy to start. Will be going back soon for the chainsaw attachment!
Date published: 2017-10-18
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Optional Accessories

  • Gearbox Attachments
    Gearbox attachments are available for this model. View the interchangeable gearbox chart to find out which attachments work with this model.
  • 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.
  • Deflectors
    Protect yourself from flying debris while trimming. Check out our selection of deflectors and find the one that will help protect you.
  • Trimmer Line
    There's high-performance STIHL trimmer line for every operating condition. 
  • Trimmer Heads & Blades
    Many trimmer heads and blades are available. Find out which ones to use with this model in this chart.  

Standard Features

  • Common Features for Trimmers
    View the features common to many STIHL trimmers.

You Will Also Need

For Your Safety


Read what our customers say about STIHL Trimmers
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 R Instruction Manual (PDF)
Download Instructions on How to Rewind Your Trimmer Head (PDF)
Product Safety Manual (PDF)
STIHL Limited Warranty
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