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A powerful and fuel-efficient chainsaw that’s comfortable to use.

Product Description

The STIHL MS 251 WOOD BOSS® Chainsaw is designed to deliver all the power you’d expect from STIHL equipment, yet with a comfortable and ergonomic design. The MS 251 WOOD BOSS® is perfect for felling small trees, pruning and thinning, and cutting firewood simply and efficiently. And with up to 20 percent fuel savings and 50 percent reduced emissions (as compared to previous models), you can enjoy a longer run time while feeling good about your impact on the environment. Features like a Master Control Lever™ and reduced vibration make the STIHL MS 251 WOOD BOSS® a lean, easy-to-use machine that still packs plenty of power.

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.

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  • Master Control Lever™
    The Master Control Lever™ is an easy to use single lever, operating the choke, starting throttle lock and on-off switch. The operator must pull the throttle trigger before moving the Master Control Lever™ to the choke position.


45.6 cc (2.78 cu. in.)
2.2 kW (3.0 bhp)
4.9 kg (10.8 lbs.)
390 cc (13.2 oz.)
198 cc (6.7 oz.)
.325" RM3
GUIDE BAR LENGTHS (Recommended ranges)
40 to 45 cm (16" to 18")
STIHL recommends #3634 (26 RM3 68) OILOMATIC® saw chain and 18" 3005 008 4717 STIHL ROLLOMATIC® E guide bar combination. The actual listed guide bar length can vary from the effective cutting length based on which powerhead it is installed on.

Important Information

* The actual listed guide bar length can vary from the effective cutting length based on which powerhead it is installed on.

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.


MS 251 WOOD BOSS® is rated 4.3 out of 5 by 471.
Rated 1 out of 5 by from Works as expected, getting parts is difficult This is not a complaint about customer service, it is a heads up to prospective buyers about parts availability.I want to buy a chain, why can't I do that online? Looks like only counterfeit chains on Amazon.I went to one location nearby, (but still out of my way) - they did not have a #3634 (the recommended chain for a MS 251 Wood Boss), now I've got to guess which location (6 in a 50mile radius) _might_ have what I need. A giant waste of time.For this reason, I'd choose something other than a MS 251 Wood Boss).
Date published: 2019-10-02
Rated 5 out of 5 by from Everything I asked for. I bought this as a step up (finally) from low end saws. The only issue I have had in the first year has been flooding the saw on a hot day once. Other than that I have been chewing through wood with ease. I have cut about 8 oak and 20 softwood trees to firewood lengths with ease. Also, a couple of tasks around the house. Still very happy with my purchase. Time to head to the mountains for elk camp again!!
Date published: 2019-09-30
Rated 5 out of 5 by from Great saw This saw is great, could be a 20" bar though but, great power. I cut down 5 mesquite trees and this thing was awesome..
Date published: 2019-09-25
Rated 1 out of 5 by from Never wants to start Have used many chainsaws over my 18 years living in the Poconos in PA. Never really had any problems getting the saws to start just didn’t like the power or cheap plastic interior parts that would melt, so when my last Chainsaw burnt up I decided to spend a little more and get a StihI because I had been watching YouTube channel “Outdoors With The Morgan’s “ and they are always using Stihl saws and blowers. I bought the saw in Sept/Oct of 2018 but could not use until June of 2019 because I was recovering from shoulder surgery. First time went to use saw wouldn’t start so took it to dealer and after 1/2 hour they got it started. Since than i’ve Had it back their 2 more times with starting issues, both times they have kept for a week and told me I must have flooded it and gave it back( no charges of course) but I think there is something else wrong with the saw because 1 use later the saw won’t start again. Very disappointed I decided to spend a little more $$$$ and I get nervous just thinking about going to use saw and whether it will start or not. Have only managed to use it for cutting wood for a total of 3 to 4 hours so far!
Date published: 2019-09-17
Rated 5 out of 5 by from MS 251 Wood Boss This little saw is perfect (and priced right) for most home / personal property use. I was impressed with it's overall performance and easy maintenance and care. I would recommend the MS 251 to anyone who is looking for a lightweight, dependable chainsaw with plenty of power to handle the job.
Date published: 2019-09-16
Rated 2 out of 5 by from Probably a defective unit but won't take a chance on a second one I used the one-year disposable box store 18" chainsaws for years. I got tired of buying a new one every year and everybody kept telling me to get a Stihl. I went to my local Ace and purchased the MS251 18" Wood Boss. Worked fine for first year and a half. Since then, even after routine maintenance it has been nothing but issue after issue. The oiler is not heavy duty enough for heavy usage of the saw. I am currently on my 3rd oil pump, 3rd worm gear, I've lost count of the amount of cage bearings, and now I am on the second engine. It is finally running decent again, but this is after practically the whole saw has been replaced. This is my third year with the saw and I hate to have to buy another saw with all that I have invested in this one. I do believe with the amount of trees/wood I cut, I will have to go bigger and heavier duty with my next saw. The MS251 isn't capable of cutting much more than a tree or two every now and then. It definitely does not like felling trees and the poor design of the oiler does not allow for using the saw in a horizontal position for much more than a few seconds without overheating and burning up bearings and ruining chains. Overall, I have been very disappointed and dissatisfied with this saw and it's underwhelming performance. Wish I would have just continued with the cheap and chinsy brand chainsaws. Next saw I purchase will be much bigger and made for actually cutting wood and constant usage.
Date published: 2019-09-14
Rated 5 out of 5 by from First saw Birthday gift from the wife, first chainsaw. Been using it for five months now. Cutting up firewood, clearing fallen trees from big storms. Loving every second of it. Easy to flood if you're newer like me. My local Stihl dealer straightened me out though. Great product, great service. Its the bee's knees. Buy a Stihl!
Date published: 2019-09-05
Rated 1 out of 5 by from Running issues Returning my 251 wood boss tomorrow. I used it for 2.5hrs, then the following day it would not start. From my diagnosis the ignition coil is bad. And of course this happens when I need the saw most.. For the little time I used it I enjoyed the saws performance. But I feel like I may need to spend a little more money and get a 271 wood boss, assuming that it's built better as it will be used more frequently.
Date published: 2019-09-03
Rated 5 out of 5 by from Ezy start up, Ezy start up, cuts like hot knife thru butterVery pleased with my new purchase Highly recommend
Date published: 2019-09-03
Rated 2 out of 5 by from Won't stay running After 20 minutes the chain spun off. OK that can happen. Worked good for about 2 hrs. Went to use it on a different day and wouldn't stay running. I'm surprised that the saw wasn't ready for some extended use. Hopefully the tech can adjust the carb. and make it more usable.
Date published: 2019-08-30
Rated 1 out of 5 by from Will not hot start, the no tool chain adjuster does not work. This saw is a nightmare to use. It will not restart hot, and the tool free chain adjuster will not adjust once the saw is hot. It binds up, and will not turn until the saw has cooled for at least an hour. Big R does not have in store service, and the two local Stihl service centers want their hourly rate to provide warranty work because I didn't buy it from them. I can't wait the six to eight weeks that Big R says it will take for them to send it in for repair. The purchase was a mistake, and I won't make that mistake again.
Date published: 2019-08-28
Rated 1 out of 5 by from Worked good, once. Bought the wood boss based on awesome reviews. Trimmed a small tree in the yard and turned it off. It never started again. Took it back to Ace where I bought it. 2 times no certified tech was available. Finally asked for my money back but oh wait, now I was past my 7 day window. While there an ex employee walked in and offered to help, he was certified. I told the manager if he could start it I would be more than happy to keep it. Well I ended up getting my money back after an hour of failed efforts. Seriously disappointed. Cost me so much time and aggravation. Perhaps I got the one bad one they ever made but I felt obligated to report here since I got nowhere with phone calls to Ace or Stihl.
Date published: 2019-08-23
Rated 4 out of 5 by from Okay saw The only saw I can compare it to is an 028 WB I purchased in 1980. The 251 is nowhere near the saw the 028 was. Once running it seems to cut fine but can be a bear to start at times. It's lighter than the 028 but that's because of all the plastic on it. Hopefully it will last as long as the 028 did but I doubt I'll be around to find out.
Date published: 2019-08-22
Rated 5 out of 5 by from Great Chainsaw with plenty of power Great chainsaw and it has plenty of power for the farmer too. I say that because I use it on the farm too. It's weight and ease of use, I wouldn't want too use anything else on the farm all day long. It's a great chainsaw to have for cutting wood. The only thing I would change is the oil cap. I have had issues with it locking closed like it should. That would be the only thing I would change. Even with that I would still say the same for this chainsaw as I did previously.
Date published: 2019-08-17
Rated 5 out of 5 by from floods easily, but solid once you know what not to do Had to go back to store for some pointers on how not to flood machine, but I've had no problems since.
Date published: 2019-08-13
Rated 5 out of 5 by from Great Saw! Everyone loves this saw. It was a frenzy of nearly cannibalistic wood chopping amongst the guys when I first got it and went camping!
Date published: 2019-08-13
Rated 4 out of 5 by from Good home owners saw First of all, i love this saw. I bought thinking i could do anything with this saw, and it will do it. The question is for how long. Keep in mind, this is not a pro saw. If you have a ton of cutting to do, get a higher end saw. Pro saws use bigger pitch chain, have more power, run faster, and have a more solid magnesium housing. This is a polycarb housing, no oil adjustment, and no chain catcher to protect the sprocket cover from a chain that has come off. You can buy the 262 catcher, and it will fit this saw. I am maticulous with my machines. I use stihl synthetic 50:1 oil and non ethynol fuel. I clean it after every use. I never have starting issues.. It's an all around good saw for what i do. Just a few things i would change. I would definitely recommend to a homeowner.
Date published: 2019-08-11
Rated 5 out of 5 by from Great saw Great chainsaw, easy to start, cuts like a dream, comfortable for continuous use...What's not to like?
Date published: 2019-08-08
Rated 5 out of 5 by from Wood boss is a beast! The wood boss starts easy, runs great, and has plenty of power. I have used other brands and will only by Sthil now.
Date published: 2019-07-30
Rated 1 out of 5 by from Very Difficult to Start This was my second chainsaw, and with a dozen wild "weed trees" to cut along the back of my property, I thought I would step up to an 18" better quality" chainsaw. I guess I should have known that I had a "lemon" right from the start. The dealer that sold it to me, always checked the chainsaws by starting them before we complete the purchase and HE had a tough time starting it. It was always a tough start for the 5 or 6 times I used it the first year. Then next year, I brought it out and never was able to start it despite employing a variety of choke combinations. Never should have purchased this dog. I refuse to pay hefty service fees to repair a 2 year old product!! Threw the thing out.
Date published: 2019-07-25
Rated 5 out of 5 by from This chainsaw makes quick work of clearing dead wood This chainsaw works excellently and cuts through tough wood like butter. The selector switch (off, run, 1/2 choke, full choke) is a bit flimsy and seems out of place in an otherwise excellent chainsaw. This saw performs great and does everything I need it to do.
Date published: 2019-07-23
Rated 4 out of 5 by from MS 251 Wood Boss Review The MS 251 Wood Boss is a good saw, but I finding it lacking (power) compared to the MS 250 that it replaced. Other than that the two saws are virtually identical. To me a chainsaw needs that straight (when called upon) power like that of the MS 250, but with the MS 251 one has to get it spooled up before making the cut, and that's not a good look for a quality saw. It is for this reason that I could only give the MS 251 Wood Boos four out of five starts. It's still a quality STIHL product, but every time I use it I miss my old MS 250.
Date published: 2019-07-15
Rated 5 out of 5 by from Great home use saw I love this saw I have 11 acres and this makes my job easier good power for money 18 in bad was plenty for me typically use couple times a month at least
Date published: 2019-07-10
Rated 5 out of 5 by from STIHL - best products out there. I've had plenty of other brand saws over the years and only a couple of those lasted several years of hard use. But even then they dint come close to a STIHL. I've had an STIHL SF 55 weed eater since1986 and it still runs great, even with little maintenance. I love the size, power, simplicity and the dependability of the my new 251 Wood Boss. I am very pleased with my purchase and hope to get many years of service from this trusted brand.
Date published: 2019-07-08
Rated 5 out of 5 by from Awesome product This saw is so lightweight and powerful, it handles the 18 inch bar well and it has been through it all and it will still start right back up after 3 years of service so far.
Date published: 2019-07-07
Rated 3 out of 5 by from This saw failed twice this year when I needed it the most. I like the saw for its power, weight and engineering. That said, it has been back to the dealer twice this past year for not oiling the chain. The first time was during hurricane cleanup in North Carolina. Yesterday it stopped oiling while cutting a hickory tree in my yard that was blown over in a storm. And yes, it had chain oil in it. I’m disappointed that I can’t trust this saw. I spent a long time researching the right saw for my needs and In the end, I went with stihl for the dealer network and reputation. I own several stihl products and have been happy with them.
Date published: 2019-06-24
Rated 5 out of 5 by from So far it has been great. Does everything I expected. I bought my saw at Westlake ACE hardware and got a good deal on it. I feel like it does a great job. It goes through wood like a knife through butter. So far I have loved it. It starts very easy and keeps running through everything I have cut so far.
Date published: 2019-06-18
Rated 4 out of 5 by from NIce Saw Nice saw all around but starting is the only fault I have with saw. It is hard to start but I may get better at starting it as time goes on. I hope so.
Date published: 2019-06-17
Rated 5 out of 5 by from great value Starts quickly and doesn’t stop working hard. Cuts well
Date published: 2019-06-10
Rated 4 out of 5 by from product does the job well easy to start and handle cuts like butter light enough to handle dealership is very helpful
Date published: 2019-06-07
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