MS 251 WOOD BOSS®


18 in. Bar

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

The STIHL MS 251 WOOD BOSS® Chainsaw is powerful, fuel-efficient and easy to use. Ergonomically designed to bring you maximum comfort during use, this tool produces 50 percent less emissions (as compared to previous models) for a smaller impact on the environment. The MS 251 WOOD BOSS® packs features like a Master Control Lever™ and easy-to-refill fuel and oil tanks, so you can worry less about st...Read More
Print Spec Sheets
MS 251 WOOD BOSS® Specifications
DISPLACEMENT 45.6 cc (2.78 cu. in.)
ENGINE POWER 2.2 kW (2.95 bhp)
POWERHEAD WEIGHT 4.9 kg (10.8 lbs.)
FUEL CAPACITY 390 cc (13.2 oz.)
CHAIN OIL CAPACITY 198 cc (6.7 oz.)
OILOMATIC® CHAIN .325" RM3
GUIDE BAR LENGTHS* (Recommended ranges) 40 to 45 cm (16" to 18")
STIHL ROLLOMATIC®
POWER SOURCE Gas
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 depending upon which powerhead it is installed.
Model Features
  • Zoom
    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.

    More Information

  • Zoom
    Toolless fuel and oil caps with retainers
    Simply lift the lever and twist the caps to remove or tighten. There‘s no need to use a tool to tighten or loosen.
  • Zoom
    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.
Standard Features
  • Zoom
    Common Features for Chainsaws
    View the features common to many STIHL chainsaws.

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.
Click to view the STIHL Limited Warranty Time Periods
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    •2.6 oz. bottle makes 1 gallon mix

    •5.2 oz. bottle makes 2 gallon mix

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    STIHL recommends a mix of 50:1 high-quality 89 octane or higher unleaded gasoline to STIHL engine oil. This same mix ratio should be used during break-in.

  • Bar and Chain Oil Zoom
    Bar and Chain Oil
    STIHL Bar and Chain oil is formulated to adhere to the bar and chain, and to reduce wear. Special agents in the oil formulation help keep sap and pitch from clinging to the bar and chain.

    Available in quart and gallon bottles, 5 gallon pails and 55 gallon drums, in both summer and winter weights.

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  • Complete Filing Kits Zoom
    Complete Filing Kits
    Kits available for the following chain types: STIHL PICCO Mini; 1/4" pitch chain; .325" pitch chain; 3/8" pitch chain; .404" pitch chain.
    Includes file guide, depth gauge, round file, flat file and two file handles in tool pouch.
    Chain Pitch File Diameter File Guide
    Part Number
    Sharpening Kit
    Part Number
    in. mm in. mm Part Number
    3/8 PMN 9.32 5/32 4.0 0811 411 8073

    5605 750 4327

    5605 007 1026

    1/4
    3/8 PM
    6.35
    9.32
    5/32 4.0 0811 411 8091

    5605 750 4327

    5605 007 1027

    0.325 8.25 3/16 4.8 0811 412 8088

    5605 750 4328

    5605 007 1028

    3/8 9.32 13/64 5.2 0814 243 3384 5605 750 4329

    5605 007 1029

    0.404 10.26 7/32 5.5 0811 412 8108 5605 750 4330

    5605 007 1030

For Your Safety
  • Woodcutter Chaps Zoom
    Woodcutter Chaps
    Apron Chaps from STIHL are made from rugged, 400-denier nylon and feature the same UL® classified protection as our other chaps. Just snap them over your pants and you’re ready to go. Sewn into the legs of the chaps are six layers of Avertic® Pro by Engtex®, a cut-retardant material designed to clog the sprocket and stop the saw chain on a gasoline-powered chainsaw in case of accidental contact with the rotating saw chain. The open back design of these chaps makes them a great choice for hot working conditions.
  • Woodcutter Helmet System Zoom
    Woodcutter Helmet System
    The lightweight STIHL Woodcutter Helmet System is an excellent choice for budget-conscious non-professional users with chainsaws and pole pruners. Designed for comfort, the vented shell provides cooling air during use, and the 6-point mount suspension provides comfortable support. The STIHL Woodcutter Helmet System is Class G certified and includes NRR 22 hearing protection.
  • STIHL HomeScaper Series™ Gloves Zoom
    STIHL HomeScaper Series™ Gloves
    Innovative keyed thumb stitching for super comfort and gripping ability. Sizes available S, M, L, XL.

Are you ready for a STIHL?

MS 251 WOOD BOSS® is rated 4.4 out of 5 by 196.
Rated 5 out of 5 by from Awesome product What a great product easy to start and maintain and very reliable
Date published: 2017-03-15
Rated 5 out of 5 by from This product has great features and power I have only used the saw to trim several 3'' to 4'' branches ,but it starts easy and is very easy to handle. It has more than enough power to do the jobs i need to do around the house and at my deer lease.
Date published: 2017-03-14
Rated 5 out of 5 by from best chainsaw I have used My wife and I are clearing 2 acres wih only this saw and our hands, and I couldn't be happier with it. Starts easy cuts through the trees with ease. I can't believe the difference it makes when you buy a quality product instead of the other 2 we have bought. Highly recommend this chainsaw.
Date published: 2017-03-13
Rated 5 out of 5 by from Great saw, light weight Great saw - well balanced with the 18 inch blade, easy to grip and use, light weight, good power to weight ratio, 3/8 chain makes quick, clean cuts.
Date published: 2017-03-08
Rated 5 out of 5 by from Great little home owners saw Easy to start light weight. Works great trimming trees and cutting fire wood
Date published: 2017-03-07
Rated 4 out of 5 by from Good product Got this saw 2 weeks ago. Full tank of mixed gas and went into cutting. Half tank through the saw and it stalled and wouldn't start nomore. So I took it back to dealer and they told me that I flooded it. How? I didn't do any adjustments. They started it up and it ran fine without no adjustments(Dealer had no clue how to fix what's causing it to flood). Next day it wouldn't start up when its cold (had choke on for 2 pulls) so I went to pulled the spark plug out and it was soak wet. Went to read the handbook manual and readjusted the carb as it said to factory specs. Now it runs and cuts perfectly fine now. Other than that I'm liking it so far. I'll see how long this saw makes it through.
Date published: 2017-03-04
Rated 1 out of 5 by from Unreliable I have had this chainsaw for three months and have had it in for repairs twice already due to factory defects.
Date published: 2017-02-23
Rated 5 out of 5 by from good saw Saw starts easily and runs good. This model has the chain with larger teeth and is an aggressive cutter. It may be more saw than the average homeowner needs.For just pruning 6" or smaller limbs, one of the smaller saws would work quite well and cost less than the Wood Boss.The Wood Boss is an excellent saw and I would recommend it.
Date published: 2017-02-15
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