SG 20

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A manual backpack sprayer for professionals that maintains constant pressure.

Product Description

When working with compounds such as pesticides and herbicides, accuracy and control are top priorities. The STIHL SG 20 manual backpack sprayer helps ensure constant working pressure, thanks to a pressurized fluid reservoir separate from the main tank. Now you can maintain constant pressure, even through refills. The sprayer is also comfortable and lightweight, helping you get through the day with less fatigue.

Model Features

  • Adjustable Support Harness
    STIHL backpack blowers and sprayers are equipped with an adjustable support harness that distributes weight evenly across the shoulders and back, reducing user fatigue.

    See it in action!


18.0 L (4.75 gals.)
40 psi +/- 10%
5.1 kg (11.2 lbs.)

Important Information

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 Moreā€¦

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.


SG 20 is rated 3.2 out of 5 by 94.
Rated 3 out of 5 by from needs some specific design improvements I’ve been in the landscape industry for twenty years, and this is the best sprayer on the market, however, there are some specific weak points in the design that could be easily improved, some of which I have read about in previous reviews, some not, as most reviews aren’t specific. The white plastic nut that connects tank to wand; this fitting should be permanent and NOT a threaded fitting. It will eventually loosen during normal use and expose the operator and will easily break if over tightened. I have never had one of the brass barb fittings with an automotive style clamp fail. Stihl- change this design to a failproof one, the barb fitting. There is another threaded fitting connecting the pump piston to the tank, this one a brass fitting, which is better than plastic, but should be also eliminated in favor of a non threaded barb fitting, as this threaded junction will eventually loosen and leak on the operator during normal operation. So stihl- on the next model, upgrade these fittings to eliminate these leak points.My next big issue is with the cap, for two reasons; one, during walking or agitation, some chemicals will spurt out of the vent in the cap, often onto the operator, and the cap itself will often leak at the seal with products with extremely low viscosity, like spray adjuvant additives (spreader sticker or methylated seed oil), 2-4D or triclopyr. (Basically, if the spray turns white when mixed with water, be careful! It will easily leak out). I cannot see any reason for the leaking at the cap seal, the o ring appears new and undamaged, no crimping or anything, and the point at which they leak is not apparently constant. I have taken to a thorough three point inspection with each tank I mix to check for leaks before putting the sprayer on my back. The caps perform without issue for some chemicals, but leaks for others. I get the most leakage on the sprayers I use the most, but the two I am having issues with at the moment are 2018 models purchased about six months ago. I would say I use the sprayers almost daily, and spray between 25 and 100 gallons per week through my nonselective tank, but less than 20 gallons per week through my broadleaf tank, so I cannot attribute the leakage to simple wear, it has something to do with the ability of the chemical inside to “escape” the seal.My suggestion to at least mitigate exposure to the operator during a mild cap leak would be to add a half moon shaped ridge to the tank at the top of the tank below the cap to direct a spill AWAY from the operator, and down the BACK of the spray tank. Also, the top of the tank is not molded incredibly well, and may, in itself be the cause of the leaking, due to improper contact between the o ring and the top of the tank. I use significant amounts of lithium grease to prevent leaks (to the degree it is acting as thread seal), so there is a design flaw here I believe in manufacturing. I say this because it is apparent when the o ring is heavily greased that it contacts the sprayer top at a slight angle, over half to two thirds of the circumference of the cap, leaving lighter pressure along a small portion of the cap. I do not remember an issue with the caps on solo sprayers, though I use the stihls now because they last longer overall when cared well for, and are much more comfortable to use and wear.
Date published: 2019-09-13
Rated 1 out of 5 by from Not worth the money! This thing is awful! Not even close to being worth the money, extremely disappointed. The pump handle is about 4 - 6” to short and needs to be pushed out away from the sprayer. My hand and elbow are on my hip pumping constantly and it’s the most uncomfortable position making it not conducive for long spraying applications. Home depot grade, cheap plastic handle failed and won’t shut off when released. Doesn’t hold pressure very well, constantly pumping to build enough pressure for a decent spray pattern. Disappointed Stihl, you missed the mark on this one!
Date published: 2019-09-10
Rated 5 out of 5 by from Great Sprayer This is a great sprayer. I use this weekly and mine is 4 years old. It must be rinsed/flushed after each use, as ALL sprayers do. This will prevent most issues. The chemicals used break down when stagnant and clog the machine if you skip this step. If you need a quality sprayer that doesn't break the bank, this is it!!
Date published: 2019-08-04
Rated 2 out of 5 by from Great Product Until you have to change the straps This is a great sprayer until you have to change the straps. There is not enough room to bring the strap back up. I had to physically widen the strap hole by drilling it out to be wide enough. It took 30 minutes to do. Now I have a hole in my tank. I am sure it will cost more to buy just a tank than to buy a new sprayer. Whoever invented the strap system is not a good engineer.
Date published: 2019-07-21
Rated 5 out of 5 by from Have two of these one bought 2011 an one bought 2015 These sprayers have served me well so far with no problems and no need to replace parts. Use one to spray weed killer and the other to spray insect and plant dieses sprays on 20 fruit trees,65 rose bushes and other flowering bushes.Have had other makes of sprayers in the past. and none of them have worked as well.
Date published: 2019-07-16
Rated 4 out of 5 by from Does what it’s supposed to do I own three sg 20 sprayers I keep one for each dominant product I spray. After minor maintenance each spring I get trouble free service weekly. I would love to see a few upgrades to the shoulder harness and a belt harness would be a big help. Units are not cheap. Not for a homeowner.Appalachian Landscape & Management - Frederick, Md
Date published: 2019-07-06
Rated 1 out of 5 by from Wasn't working out of the box My brother bought this and let it sit on the shelf for a couple years before I bought it from him. Out of the box the pressure reservoir isn't working and will cost as much to fix as to just buy a new one. It's our own fault for not using it earlier but I thought Stihl had a better quality than this, very disappointed.
Date published: 2019-06-17
Rated 4 out of 5 by from Seems like a nice unit. Wish reserve tank was larger. The sprayer seems to be well built. Builds good pressure quickly, the heavy duty Continental hose should last a long time, and the nozzle is impressive too.Assembly is simple, and maintenance is easy and reasonable. My only gripe is the unit doesn't stay pressurized for long during use. Upon reading the summary of the unit, I had assumed I could pump it and use it for a few minutes before having to pump it again. If you want good flow, you are going to have to pump it constantly. This makes use rather fatiguing.
Date published: 2019-06-15
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