9 Reasons Why The Stihl MS391 Is Considered The Worst Stihl Chainsaw

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Is the Stihl MS391 any good?

I recently ran a poll to find out what people think is the worst Stihl chainsaw.

The winner of the poll was the Stihl MS 391 by a clear margin.

And while that might not make you feel too positive about the saw, especially if you’re looking at buying one, it doesn’t mean it isn’t right for you. While there are a lot of people out there that hate it, there are many who really love the 391.

I’ll present both sides of the argument so that you can determine whether or not it might be right for you.

*Used Stihl MS 391 for sale here on eBay.

Stihl MS91 Chainsaw

worst stihl chainsaw

The Stihl MS 391 price is around $740.00 with a 25-inch bar – check the latest price here at Ace Hardware.

It’s recommended for use with bars from 16-inches to 25-inches, but in my opinion, 25 is probably a bit long.

It’s a 64cc, 4.4hp chainsaw so it runs really nicely with a 20″ bar. Buying a new 391 with a 20″ bar will be a bit cheaper at around $679.00. I think that’s the best bar length for this saw.

The 391 is not a pro saw, but it’s at the top of the range of non-pro saws. Stihl describes it as a”farmer’s chainsaw” or for “for agriculture and horticulture.”

It is a farm and ranch chainsaw that is good for firewood and the odd felling job.

Dealers also have the following description.

The MS 391 features our newest engine technology that adds fuel efficiency while reducing emissions as compared to other models. Though equal in weight, the MS 391 is more powerful than the MS 311.

Add to that an optimal power-to-weight ratio and you have a chainsaw that’s cut out for the big jobs in field, farm and ranch. Felling trees, cutting firewood and cleanup after the storm just got a whole lot easier with the rugged MS 391.

But while it’s described as having “an optimal power-to-weight ratio,” this is perhaps the biggest complaint of those who dislike the 391 – it weighs too much – but we’ll get into that shortly.

Stihl MS391 Specs And Features

  MS291 MS311 MS391
CCs 55.5 cc 59 cc 64.1 cc
Horsepower 3.7 hp 4.2 hp 4.4 hp
Displacement 3.3 cu in 3.6 cu in 3.9 cu in
Weight 12.1 lbs 14.1 lbs 14.1 lbs
Bar Length 16 – 20″ 16 – 20″ 16 – 24″

The Stihl 391 entered production in 2009 at the same time as the Stihl MS 311.

You can see when comparing the 311 and 391 specs that the 391 does look like the better saw. As stated in the description above, they weigh the same,e but the 391 is giving you a good chunk more power.

The 311 also made the top 10 worst chainsaws, but there were a few other factors that turn people off the 391.

MS391 features:

  • Reduced-Emission Engine Tech – lower emissions
  • Stihl Quickstop – a chain brake for safety in the event of kickback
  • Anti-Vibration System – a standard feature on all Stihl saws that makes longer operation easier
  • Stihl ElastoStart – for easier starting
  • Ematic Lubrication System – for reducing chain oil usage
  • Adjustable Oiler – control the flow of oil to the bar
  • Side Access Chain Tensioner – for tightening or loosening the chain
  • Master Control Lever – choke, throttle-lock, and on/off all one switch

Some of these features, such as ElastoStart,  are not seen as a benefit by all Stihl users as they believe it limits power or sets you up for more issues.

Stihl MS391 Problems


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So whats wrong with the MS 391?

I searched around to find out why and here are some of the common problems that 391 owners state.

Why people do not recommend the 391:

  • The 391 is heavy, problematic, hard to work on, certain parts are hard to get atm, and it’s poor value.
  • The real problem with the 391 (and all Stihl clamshells really) is the price. They’re far too expensive new for what you get.
  • I believe the 261 is far superior in terms of built quality… about the same price and better built. The 391 has a bit more torque but this doesn’t make it better in my opinion.
  • It seems like most 391s end up eventually dying from a massive air leak caused by the cheap transfer port covers Stihl used on the side of the cylinder. They’re glued on and it seems they fail on all of them at some point. I’ve been asked to fix a lot of 391s with this type of failure and on almost every one the piston is destroyed inside the cylinder. They are fine for homeowner use but they don’t last too long commercially.
  • One thing that I hate is how quick the fins get clogged up with debris and gunk. I’ve never had a saw do it so badly. Some saws I’ve owned don’t dirty up the cylinder at all. Yet this thing every three full days cutting has the fins between the muffler and the cylinder totally closed over.
  • Some 391s have issues with the glued-on transfer caps coming loose and causing air leaks so watch that. I have a pile of ms 311-391 saws that are now parts saws, some were only a few weeks to a few months old.
  • Besides it being heavy and having lots of issues I’ve had the muffler bolts coming loose. I decided to spend the extra money and go pro.
  • The 391 feels powerful at first but once you break them in they’re weak and oversized.
  • Yeah, I have knowledge that they blow their pistons. Other than that it’s a boat anchor, have used one, and they’re s**t. My old boy has a 311 on the farm and the clamshell is better.
  • The 391 is a clamshell design motor in the homeowner’s category and once it gives up not worth fixing back.
  • The MS391 is underpowered for its weight.
  • It’s worth hanging off the back of your boat…

So that’s a summary of some of the issues, problems, and potential problems.

Chris summarized his thoughts:

I think there are three main points when it comes to the 391 being the worst saw ever made.

  1. It’s a clamshell. This really offends all the “buy a huge pro saw to cut firewood on one camping trip a year” idiots.
  2. The power-to-weight ratio isn’t as good as a pro saw. This is because it isn’t a pro saw.
  3. There’s not much aftermarket for them. This is because it’s not a pro saw.
  4. It isn’t a pro saw. This is because it’s not a pro saw. Did I mention it’s not a pro saw?

And while that doesn’t quite cover all of the reasons people give for why you should not buy a 391, it does emphasize that you shouldn’t be expecting a pro saw when you get one.

Stihl MS391 Pros

Check out the Stihl 391 being used for the first time with a 25″ bar in this video. 

Brock from Rockhill Farms also compared the 391 with the Stihl 250.

Here are some other positive comments on the Stihl 391 from FB groups:

  • I have owned a 391 for four years. 25-inch bar and it is a great saw. Never had an issue with it.
  • Love mine Had mine for about 10 years and other than filter and spark plug change it goes like a hot knife through butter!
  • I’ve seen a few 391s that have been to hell and back, they all run perfectly.
  • Yes great wood cutting saw firewood
  • Yeah, a bit heavy but a good reliable saw!
  • I don’t mind my 391, sure it’s a little heavy but it runs well. But I would definitely prefer a pro saw if I ran them every day. I love my 250 though. Best saw I’ve had I think.
  • If you stay out of the dirt, keep them sharp, and make sure the bar is oiling, they will serve you well.
  • 391 is a bulletproof saw in my opinion. It’s a little heavy but will last forever.
  • I feel a 391 with a 20″ bar is a great saw.
  • Let me just say, for an average weekend warrior or a farmer with the need to cut a decent tree a few times a year… the 391 ABSOLUTELY will meet your needs. For the negative Nellie’s out there, just remember that not everyone is cutting daily. The 391 is a good saw for those questioning.

And a final long comment:

While I am not a fan of the 391, it is by no means their worst saw. It’s actually a rather solid saw overall. But not when compared to others in the price range. All it really is is a ‘big bore’ clamshell saw. A heavier-built homeowner saw.

That said they seem to hold up well. My buddy has an MS270 that has cut more than many pro saws see in their respective lifetimes, but not because it’s better built. It’s just adequately built and not everyone needs a pro saw.

It cost the same as an ECHO 620p, which is better than the 391 in quite literally every way. Same goes for the Dolmar/Makita 6100.
And it weighs as much or more than these superior legitimately pro-class saws.

For the money, capability, and overall everything, the ECHO 590 is a much better purchase. I grew up running Stihl chainsaws. But the ECHO 590 is just a better saw. I’ve run both side by side as my brother has a 391 and I have a 590. Again, not a brand snob here.

I think that sums things up really well.

Stihl 391

The 391 is a good saw for firewood and felling trees (infrequently).

It’s not a saw that you should use every day for commercial or pro use, but as a farm and ranch saw it’s all good.

Ultimately, most people prefer the MS261 over the 391 – it’s a 50cc saw but it’s said to be better built and it doesn’t suffer from the same problems.

The Stihl 036 is another good alternative – it’s a 61cc saw, along with the Stihl MS310 – a 59cc saw.


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6 thoughts on “9 Reasons Why The Stihl MS391 Is Considered The Worst Stihl Chainsaw”

  1. I had an 036 rebuilt instead of buying a new saw. I’ve used both side by side and the 036 is lighter and faster. Put the bar on the 391 that the 036 was running and there was no comparison. In my opinion you have 2 choices when you shell out money for a 391. Step down to the 261 and save your back and a few bucks or go up to the 362 for a few dollars more and a still lighter saw. The 391 kind of lives out in no mans land at its price point

  2. Bought the ms 391 in 216 to go along with our other saws as we needed something bigger that wouldn’t get used very much other than on some big tree now and then. It is the biggest piece of junk we have ever ran. Within the first month we tried to take it back and get our money back. It never ran right from the beginning and NEVER started back up after it was warm. You could hang it up after you shut it off for the day. I just brought it in to my shop to try to get it ready for the storm, it would not start even with putting fuel straight to the carb. It hardly has any compression as I tested it and you can shine a light threw the spark plug hole and see the cylinder is shot. Of course the dealer won’t help at all being the saw is a few years old now and just claims “we put straight gas in it”we’ll the other 4 saws we have, we have never had an issue out of. Not sure if I just got a lemon or if all these models are junk but either way I won’t buy one again and I won’t go back to R&J in Palatka fl again for anything since they don’t care to even try to help anyone out.

  3. My 391 is a piece of S:&$t. It is problematic starting, and if you are an amateur arborist like me a miss cue the start procedure, the bitch will not start till tomorrow when you do exactly the same process and it starts first time. It obviously is not designed to run 2 days in a row. I’m going to throw it thru the sthil shop window, I’m that frustrated. Don’t buy one and check very carefully.

  4. I bought a 391 about 5 years ago to replace my 056 magnum that the ignition went out on and get something a bit lighter. I’ve cut abouts 2 cords a year with it and it has been flawless. Starts right up hot or cold and runs great. It isn’t as powerful as the 056, but I didn’t expect it to be.

  5. I have had my 391 for 7 years now, and 25” bar with sharp chain and good fuel mixture, have had no issues.
    It cuts and runs like a stripped @&$ Ape.
    3-4 cords a year for myself and felling with some friends , along with slabbing


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