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Stihl MS 390 / MS 391 Farm Boss

Stihl MS 390 / MS 391 Farm Boss

391 FarmBoss and MS 390
3.5 from 32 reviews


Got my MS390 5 years ago, been cutting Australian Hardwood to fuel our furnace which heats a large Queenslander home. We get down to minus 11c in winter outside. This saw has not missed a beat and we go through a lot of wood! My wife likes the house very, very warm. Would not swop this saw for a new model, just replace anything that needs it. Keep up the oil. Mods done, Polish the ports & open up the muffler and "super tuned" (google it). Run a full chisel teeth and keep them sharp. If you can persuade someone to sell you one second hand, grab it with both hands.

Purchased in January 2014 at private seller for $600.00.

Build Quality
Value for Money
Ease of Use
Cleaning & Maintenance

Perfect Saw

I have owned Stihl for over 30 years, I purchased my Farm Boss about 3 years ago, I keep it in a unheated Barn in sub zero Pocono Mountain weather. It always starts easily and is one of the best cutting saws I have ever used. The only thing I do special with this saw is I use the pre-mixed fuel Stihl fuel.

Purchased in May 2016.

Build Quality
Value for Money
Ease of Use
Cleaning & Maintenance

Stihl chainsaw is a disgrace

I bought a Stihl chainsaw 3 years ago. Didn't use it much because I didn't have time. Now I'm retired and have trees that need cut. Got it out of my climate controlled garage, and the housing cracked when I started to use it. Bar oil just runs out of it. Took it to dealer to find out the housing costs as much as the saw did. I haven't cut 2 chords of wood with it. It is junk. I will never buy a Stihl product. This saw is very disappointing.

Purchased in August 2016 at Stihl Dealer for $399.00.

Build Quality
Value for Money
Ease of Use
Cleaning & Maintenance

Blown engine

Probably got 10-15 hrs of use out of it. Didn’t use it much but it’s still barely out of warranty. Really like my ms290 but obviously quality has dipped dramatically.

Purchased in March 2018 for $600.00.

Build Quality
Value for Money
Ease of Use
Cleaning & Maintenance


Don't buy Stihl , I bought a stihl MS250 for $695 and motor died after 4 months ( or 10 medium tress cuts) . Stihl dealer said we didnt mixed enough oil and refused to pay the repair motor cost of $475, But we always mixed 100 per 5L. We bought the MS391 while we waiting for the dispute. Buy after few days use, the MS391 wont stop now we have to bring it back to repair. SO DO NOT buy STIHL produsts, waste time
Annie from New Zealand

Purchased in February 2019 for $1,295.00.

Build Quality
Value for Money
Ease of Use
Cleaning & Maintenance

don't buy 391, no back up and Stihl blame operator

I have owned many chainsaws over last 25 years through our hardwood timber biz, recently bought 3 units 391 and 1st unit lasted 4 weeks when compression died and can see a hole in piston after spark plug removed. all 3 units are not working with same problem, usage is moderate and maintained. enough power but no reliability and Stihl will not support unless we pay money to repair. very poor form. Careful what you buy and as newer Stihl saws too many electrics and lighter wight, not as robust. using my 20 year old 268 Husky rather than 391 with latest features but no performance. by the way my 18 month old 381 is running well!!

Date PurchasedMay 2018

Fantastic saw

Owned my 390 since 2008 it’s always started and cut over 100 ton of hardwood , jarra, stringy bark yellow box iron wood black wood white gum
It’s always started you have to follow the procedure
Choke on pull till it has the first fire then flick the choke to fast idle put chain break on then it starts flick the accelerator and it idles
I always clean the air filter and measure my oil with a measuring cup to 5 litres of petrol
After use I always take the bar off and clean with compressed air I run a file across the teeth at 30-35 degrees to sharpen only 2 passes needed
I've never taken it in to a dealer iv changed the plug once in 10 years
I just cut 10 ton of wood this week thought how good this saw is !!!

Date PurchasedJun 2008

Good saw if only it would run all the time (2)

Follow up to my last review where I could not get the saw to run. There is a specific starting procedure that makes it run. First, pull the trigger all the way, then flip the choke lever to full choke. Pull the starter cord 3 times, not 4 times, and not 2 times, 3 times only, then flip the choke to half choke and pull away, it should start with in the first 2 or 3 pulls. If this doesn't work, it is flooded, and you need to pull the spark plug, spin it over to get rid of the gas and start the procedure over.
Still cuts amazingly well once it gets going.

January 6th 2019 Update: Good saw if only it would run all the time (2)

January 2019 Third follow up to my review over the summer of 2018. I still have the same saw. The local dealer got sick of seeing me because shortly after following my exact starting procedure, I could not get it to start again. After they spoke to Stihl and got no help, the dealer swapped the entire ignition module out. Although it is still a little touchy to start, it is well with in what I would expect from a reasonable chain saw.
The previous sequence I listed with certain number of pulls etc. really had nothing to do with anything.
Put on the choke, pull a few times, it may or may not start. Flip to half choke and pull until it starts. When it's cold, this should be a few pulls but you should see some light smoke or hear it trying to start and then it does.
My saw now runs great and cuts amazingly. It is a heavy saw, so this makes it great if you are bucking up pieces of wood already on the ground. It's not so great for overhead branch trimming work. I am a 53 yr old carpenter in very good health.

Date PurchasedApr 2018

Good when going but hard to start and died early

Bought the farm boss to cut blanks for turning and slab cutting for furniture. Had a fair bit of work clearing fallen trees after recent cyclone and some cuts of a full tank at a time doing slabs. After 11 months and about 20 hrs work it upped and died. Always used 40 to 1 mix but it had lost power and stopped 10 min into a slab cut,never to go again. Dealer says I cooked it but I would expect it to cope with long cuts at high revs. No fouling of air vents or other contributing factors. Starting always a bit of an issue. Never less than 6-8 pulls and often flooded and needed a rest

Date PurchasedJul 2017

Great chsinsaw

Husband very happy, wish we had bought one 20 years ago. Slices through sugar gum like butter, makes the job so much easier. Light to hold and to maneuvers. Received a free chain with it , so wuite a bargain. Wishes he hasn't wasted his time with inferior brands & got one of these years ago

Date PurchasedJun 2018

Stihl - Excellent chainsaws

We bought two of these saws. Used both for cutting wood all day long. Sharpen one while the one one is cutting. Used a 20" blade for low down torque. Excellent saws. Had them for years now and never let us down. Yes they can be a bit temperamental, but what chainsaws don't? Far better than any other brand I've owed. Crushed oleo-mac it was that bad... Great saws, still have them. For those who don't know how to start them, push the fuel primer six times, then pull the choke and pull start until it wants to start. Then push it back in and pull start. It should start every time like this. Had these saws for many years now and very seldom had an issue if you follow this procedure given by dealer.

Date PurchasedApr 2003

wish I would have never bought it!

Really hard to start in any weather. Floods fast. Like Luke said, "shop shelf decoration". some tell you to pull it ounce on full choke, ounce on half choke, then switch to run, and it will start. Wrong! Others say, pull on full choke till fake start, then on half, at witch point it will start. then release the trigger back to idle. Wrong!
No wonder they discontinued it. Also went through an ignition coil before it had 50 hours on it.

Date PurchasedJan 2014

Muffler keeps coming loose

The saw works great but the 2 bolts keep backing out on the muffler. I tried putting lock tight on the bolts but that didn't work either. I'm taking it back to the dealer to see what the problem is. I own 3 other Stihl saws have never had a problem. I think this is a design flaw my other saws have all thred bolts with nuts on the muffler this saw has bolts that go into a small hole in the muffler that are very hard to get to.

Date PurchasedApr 2017


Crap chainsaw wouldn't start dealer said wrong fuel mix I said you told me 50/1 . Other 2 chainsaws still going on same fuel mix . They can fix it for $800 wow only used it 6 times .be careful when buying Stihl chainsaws and whatever they say don't use 50/1 mix asking for trouble

Date PurchasedOct 2016

15 minute saw

Bought MS391. Dealer prepped and started. Oil in, proper dealer sourced ethanol free premix. Saw blew hole in piston within 15 minutes of normal operation (not under excessive load). Dealer dismantled and consulted with regional Stihl warranty representative. 6 weeks later I call to relate story. I am told I pushed it too hard, i.e., my fault. Unbelievable! I have used an MS170 with same fuel, on same logs with same method ripping 600 lineal feet t/- with no problem and still running strong. This big new saw did not last 4 feet. Stihl wants me to pay for the labor of repair. Out $629.00, six weeks of down time and anticipating using a saw I have no confidence in after paying extra labor cost I should not owe. Poor business practice. Way to loose customers. Shelf decoration for shop, but not a chainsaw that cuts wood.

Date PurchasedApr 2017


I brought a 391 for general wood cutting. It was used 6 times with each time being less then .45mins max.
Blew a hole in the piston. Stihl blamed the fuel, all saws were run off the same fuel that day.
Dealer would not warrant the saw was less then 9 month old or would head office on dealers recommendation.
Had an independent replace piston, same thing happened fuel tested and all good. Looks like when warm it developed an air leak.
I have a lot of stihl products including a mini boss which has done a lot of work and has never fail.
Would not trust stihl or their products after dealing with them over this issue.

June 26th 2017 Update: Blowing pistons

Blew piston fuel was good. Suggested air leak but was told I was overloading the saw. Was cutting rounds 150mm - 250mm for meters stove. Only used 6 times chains always sharp. Still wouldn't warrant.
Replaced piston same thing happened independent mechanic found an air leak in crank case when heated up.

Date PurchasedJun 2016

bought a391 stilh

i just bought a391 second hand from Gumtree ,2 months old . have used these before,great saw i need a bit more grunt than my 311 to cut red gum. cutting another load of redgum on Sunday. Will see how it performs against my 311 in performance ... like i say look after them ,they will last along time.

May 8th 2017 Update: chainsaw

l just came back from ballarat with a trail of red gum.l used my 391 stihl ,it performed like a dream. Going back Friday for another load , people who have trouble with the saw STOP complaining about them , l have 2 saws now,311,@391, both working perfect,if you have trouble ,take it back and ask them how to start them ,the whey they do it , l have no trouble with my dealers in geelong ,they are very helpful giving advice , no harm in asking them ,clean your saws after each use ,they wont let you down. Ron

Date PurchasedMar 2017

Chain bar does not stay in place, chains by Stihl do not last. Worst problems I have ever had

Stihl has two bolts that take two nuts supposed to hold the bar in place to enable holding the chain taught on the bar. The system does not work. I can cut just a small amount of brush, or a tree and the chain loosens and until I figured out the cause of this spanking new chain saw, the chain came off the bar several times. I feel cheated by the Manufacturer for building such a poor product.

Date PurchasedMay 2016

Bad gas - my...

Bought my first Stihl saw today, an MS391 with a 25" bar. The dealer sold me 3 additional chains and synthetic oil for the fuel mix, put chain oil and gas in it, and I was on my merry way.
On the way home I bought a new gas can, topped my truck up with ethanol free regular and filled the new can after having poured one container of oil in it.
At home I started it up following the handbook, and decided to "practice" on some walnut (got a big oak to work on!). After half a tank, it was tired and bogged down on 4" stuff, and after 3/4 tank it stopped.
I decided to fill it up with my new gas, when I noticed, that the stuff that was in the tank was clear, without any sign of dye from oil.
It started up with lots of tries, but only ran for two secs or less.
I brought it back and told the sales guy, that maybe the service guy put straight gas in it instead of mix.
They tinkered with it, replaced the fuel filter and then told me, that I had simply used old gas, and that they could clearly smell it.
- That's when I got agitated and I told the sales guy, that I think they ruined it from the start and I wanted a replacement.
I was told, the MS391 is a rare model, and they'd have to order one, which might take a couple weeks.
I said, I am not taking the one they sold me back.
They found a replacement power head in 30 seconds - oy!
When they handed it to me with my used bar n chain as well as cover plate, I asked them if they had put gas in it.
"Of course" was the reply, and I made them dump it - didn't want #2 be conking out also.
Sofar, it's no better than my six year old 33cc Poulan, which should tell the reader something.
Disgusted with dealer, dubious mechanic, and lies ("got to order one..."), as well as underwhelming performance.
I hope, this one "wakes up" and will actually work.
I'll see.

Date PurchasedApr 2017

Awesome saw

This is my first chainsaw and have owned it now for 5 years.
Only problem has happened recently when the clutch drum E-clip broke without me knowing and hence the retainer clips on the clutch have broken as well. Easy to fix myself with getting the parts from the local Stihl shop.

Date PurchasedMay 2011

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Questions & Answers

Stihl 039 are they a good saw for getting firewood can buy a second hand one for $400 is that a good buy
No answers

Purchased 391 July 2018 used it for about an hour in august, no probs,heaps better than my old 039 that it replaced after 20 trouble free years. Last sat, Feb23,used the 391 and my ancient 024 to cut up a gum tree that came down at xmas,024 as usual no probs, 391 difficult to start,kept flooding,in the end full throttle and kept pulling till it started. It ran well for about 40 mins then DIED,hole in piston!!Used the same fuel,mix,stihl oil and 95 ulp, in both saws and same cutting technique. Can only guess that carby set too lean at factory,faulty crank seal,or just a crap chainsaw??? Any ideas??
No answers

Will a piston and cylinder from a Stihl MS390 work on a Stihl MS391 ?
No answers


391 FarmBossMS 390
Price (RRP) $1,399.00
Bar Length50 cm
Weight6.2 kg5.9 kg
Engine Displacement64.1 cc64.1 cc
Fuel Tank Capacity600 mL
Release dateMar 2008

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