Welcome to our Husqvarna 120 Mark II Review, as well as general discussion on all the current Husqvarna Mark II chainsaws, a new series incorporating next generation technology to make Husqvarna chainsaws even better. Most of the innovation is in the professional 550 XP Mark II and 545 Mark II, which we’ll talk about later in the article. Is this the right chainsaw for you? In 2022, you can buy cordless chainsaws with as much power as a 45cc chainsaw. Just something for you to consider. Most homeowners are better off with a battery-powered chainsaw, and some people have a need for gas, especially if they’re felling large trees or have a need to cut large volumes of firewood. The right chainsaw for you completely depends on the scope and size of your wood cutting tasks are.
Intro | Husqvarna 120 Mark II
Husqvarna has been hard at work, researching and developing a full line of consumer and professional chainsaws to stay a leader in the chainsaw market. The value of Husqvarna resides in the quality of the internal components, which you don’t see, but you will come to realize over time in seeing the reliability and overall efficiency of the saw. IE. Runs cooler, cuts faster.
VIDEO | See the Husqvarna 120 Mark II in Action
Arborists, professional loggers, landscapers, and pretty much anyone with an interest in the latest chainsaw news would have heard that Husqvarna released their brand-new “Mark II” lineup of 50cc prosumer chainsaws a couple months ago. For now, this lineup consists of 2 main models – the 550 XP Mark II, and 545 Mark II.
There are also special “G” versions of these two chainsaws, i.e. the 550 XP G Mark II and 545 Mark II. These “G” versions are specialized for operating in extremely cold conditions (freezing temperatures), which is why they are equipped with heated handles and heated carburetors. All that is great, but most homeowners don’t really want to spend big money on 50cc prosumer models. After all, how often do you cut wood every year? A couple times at the most, if you’re the average person who just wants to prune some trees in the orchard or work on the occasional DIY home improvement project.
Husqvarna 135 Mark II / 40.9cc : A Better Buy
More Power than the 120 Mark II
Between all these exciting announcements from Husqvarna, two very interesting models managed to slip underneath the radar – the 120 Mark II, and the 135 Mark II. The complete set of technological improvements made in the 50cc segment doesn’t carry over to these 2 homeowner models, but they are still considered massively better than previous gen homeowner saws from Husqvarna. And we shall also demonstrate how the 120 Mark II is better compared to the rival model from Stihl in the same segment – the MS 170.
There was no Husqvarna 120 Mark I, so you might be confused as to why they called the new model Mark II (for 2nd generation). In fact, it is pretty much a redesigned Husqvarna 240 with very similar specs (same engine, similar feature set, slightly larger fuel tank than the 240 and higher chain speed). As for calling this one a 2nd generation Husqvarna 120, there is indeed a first generation model which can only be purchased in India – the 1st generation Husqvarna 120. Compared to the newer 2019 version of the Husqvarna 120, this 1st generation model features a smaller engine (35cc vs 38.2cc). The 1st generation 120 also has a much inferior vibration dampening system and uses more fuel since it is not powered by an X-Torq engine.
In this article, we’re going to review the Husqvarna 120 Mark II and explain why you should purchase this little 38.2cc gas chainsaw if you’re a homeowner, or perhaps, consider buying the 135 Mark II, which has more power. It can also be used in professional environments, for limbing and pruning fallen trees. Read the entire article to learn more about the changes introduced by Husqvarna in their next generation chainsaw lineup, and how these new design choices affect various chainsaw parameters such as – durability, performance, comfort, fuel efficiency, etc.
We’ll also talk about exclusive Husqvarna technologies such as air injection, X-Torq, automatic carb adjustment etc. and compare these with innovations made by Stihl to give you a better idea of how these 2 chainsaw giants stack up against each other in 2019.
Consider A Cordless, as A Gas Chainsaw Replacement
If you’re interested in more chainsaw options, I recommend reading our guide to the best gas chainsaws, or, might I be so bold as for you to consider a powerful cordless models as a gas replacement. Yes, you can get a battery-powered chainsaw equivalent to a 45cc gas chainsaw, like the 80V GreenWorks (16″), as one example. Consider it. Technology has come a long way in the past two years.
Features Overview / Technology : Husqvarna 120 Mark II
Features : (Husqvarna 120 Mark II) :
- Air Injection : Centrifugal air cleaning system removes larger dust and debris particles before reaching the air filter. This results in reduced air filter cleanings and improved engine life.
- X-Torq : Delivers lower fuel consumption and reduced exhaust emission levels in accordance with the world´s most stringent environmental regulations.
- Combined choke/stop control : Allows for easier starting and reduces the risk of engine flooding.
- LowVib : System designed to reduce vibration levels to the operator, which lessens fatigue.
- Air Purge : Inertia activated chain brake
- Cylinder displacement : 38.2 cc
- Power output : 1.88 hp
- Weight (excl. cutting equipment) : 10.7 lbs
Who is the Husqvarna 120 Mark II for?
Due to its lightweight construction and a power rating of just 1.88hp, we believe the 120 Mark II is best utilized in the hands of homeowners who want to carry out light duty work. If you are cutting overgrown branches in your backyard or slicing through some 2 x 4 for a project, this is the perfect gas powered chainsaw for you. It has a dry weight of just 10.7 pounds without the cutting equipment installed (bar + chain) — and fully assembled, with bar oil and gasoline this 16” chainsaw is still pretty light at just around 17 pounds.
One huge advantage it has over the model it is replacing (Husqvarna 240), is the larger gas tank. While the 240 had a small 0.0175 gallon gas tank, the 120 Mark II boasts a far bigger belly with a 0.073 gallon tank.
Thanks to this increase of nearly 321% in fuel capacity (you heard that right), the 120 Mark II can run much longer than the 240 (even though both are powered by the same X-Torq engine). Which means, you can actually take this chainsaw out into the woods without having to carry a lot of extra fuel with you if you want to gather some firewood. You can even use it as a pruning saw to complement your large felling saw which may have a 60cc engine and a 30” bar.
The Mark II series of chainsaws have redesigned flywheels and new clutch systems to reduce rotational inertia and provide quicker throttle response. Which means this is a great chainsaw for limbing branches off a fallen tree, since you get immediate feedback when you press that throttle, a quality which comes in handy when you are weaving your way through thick brush or tangled up branches.
VIDEO | Unboxing the Husqvarna 120 Mark II (38.2cc)
Low weight alone isn’t what makes this such a good pruning and limbing chainsaw, the redesigned chassis for Mark II series chainsaws comes with increased vibration dampening which further accentuates its lightweight nature. When you operate a chainsaw for extended periods of time, it isn’t the weight alone that tires you down, but also the constant vibrations which mess with the blood flow around your hands and wrists causing serious discomfort. All Mark II series chainsaws have an improved version of Husqvarna’s patented LowVib anti vibration mechanism, which isolates the engine vibrations from the handles with a combination of springs, washers, and rubber dampers.
The 120 Mark II is also very easy to start compared to other gas powered chainsaws, especially the larger models (50cc and above). This is because of an “Air Purge” system, which is basically a primer bulb that removes air from the fuel system (carburetor and fuel lines) so that you can start the chainsaw with fewer pulls. It ensures that every time you pull the cord, the correct ratio of fuel and air mixture is pumped into the cylinder.
Often times when you leave your chainsaw sitting for a couple weeks, the carburetor may get gummed up and the next time you go to start the chainsaw it will sputter to a stop no matter how many times you pull the cord. This is because the carburetor cannot draw fresh fuel into the lines, and the decomposed fuel clogging the lines isn’t combusting properly. In other cases, you might have just removed and cleaned the carburetor + fuel line system so there is no fuel in the carburetor at all.
In this case, you need to “prime” it just like you would prime your pool pump for it to pump water. That is when you press the air purge to “purge” air from the empty carburetor and replace it with fresh fuel from the gas tank. Many gas powered chainsaws in this price segment either lack a primer bulb or feature one of inferior quality.
How does the Husqvarna 120 Mark II perform?
One thing you will notice while reading the official specifications sheet for the 240 and 120 Mark II, is that both these homeowner saws use the exact same 38.2cc X-Torq engine. However, the 120 Mark II produces less power at 1.88 hp compared to the 2hp rating of the 240. This is with the exact same maximum engine rpm of 9000, which means Husqvarna probably de-tuned the 120 Mark II’s engine slightly through some carburetor tweaks to increase fuel efficiency and lifespan of the engine.
However, we are happy to see that cutting performance of the 120 Mark II has improved slightly over that of the old 240. This is because of a slight bump in maximum chain speed – 55ft/s compared to 53.48 ft/s. Will you actually notice this 2.8% increase in speed while cutting wood? Probably not, since it won’t come into play if you only cut a few branches here and there around your property, or a couple of 6 x 6 boards. You would have to go through several trees a day to notice a significant boost in productivity with this marginal cutting speed improvement, but the main takeaway here is that you can cut much longer compared to the 240 without losing any performance.
Husqvarna 120 Mark II vs Husqvarna 240
The 120 Mark II will have no trouble going through 10” logs of pine, oak, maple, cherry, etc. but make sure that you don’t run it through several thick logs one after another because this is after all, a homeowner saw and not a professional grade model. The engine and air filter cannot withstand all the heat and debris that will be created with continuous heavy duty logging, so we suggest using it for lighter jobs like limbing and bucking small logs (up to 10”). You can also use the 120 Mark II for post storm cleanup, since electric chainsaws don’t run without power and cordless chainsaws will eventually run out of power.
Fuel efficiency and reliability : 120 Mark II
The 120 Mark II and 240 both use Husqvarna X-Torq, 2 cycle engines for improved energy efficiency. Air filter life and engine cooling is improved due to Air Injection technology which uses centrifugal separation around the flywheel to capture larger debris before it gets to the air filter. The flywheel serves two purposes-
- It stores and carries the rotational momentum between each consecutive power stroke of the engine, allowing the crankshaft to turn smoothly.
- It contains cooling fins which suck air in through the side cover to cool the crankcase and cylinder
Cooling performance is further increased on the 120 Mark II through the usage of high airflow filters, optimized airflow paths, and increased cooling fin count on the cylinder. A cooler engine is guaranteed to last longer and perform better on a consistent basis. X-Torq technology reduces emissions, while also keeping noise levels low at 109 dB(A).
VIDEO | Husqvarna X-Torq Engine
With a 120 Mark II chainsaw, there is little to no chances of you accidentally flooding the engine by pressing the choke one too many times. Regular chainsaws have a separate engine start/ stop switch and choke, so if you press the choke while the engine switch is in the OFF position, all you’re doing is flooding the cylinder with liquid fuel which will result in lots of wasted cord pulls, black smoke, and possibly a damaged engine. With the 120 Mark II, every time you set the choke into CHOKE position it will simultaneously set the engine switch to RUN. To stop the engine, you simply push down the red start/ stop switch into off position.
How Safe is the Husqvarna 120 Mark II?
Safety is the one thing you cannot compromise on, be it a 30cc beginner’s chainsaw or a 100cc tree felling beast used by professional loggers. So how does the 120 Mark II fare in this regard? Quite well actually, with an inertia activated chain brake on the front, and a throttle lockout switch located right above the rear handle. There is a chain catcher on the underside to quickly grab a stray chain which would otherwise whip out at your arms or legs. And the bucking spikes are made of good old metal instead of plastic, so you don’t have to worry about your chainsaw slipping accidentally while you are bucking a log of wood.
The ergonomics are spot-on, so you can get a perfectly stable grip on the chainsaw with both of your hands no matter how short or tall you are. Finally, we’ve got the LowVib vibration dampening system which is probably the best in the entire industry. Husqvarna knows this too, which is why they proudly display the equivalent vibration level for every single one of their chainsaws on the official specs sheet. Very few manufacturers state this number publicly.
Husqvarna X-Torq and Air Injection
Back in 1998, a power equipment manufacturer called RedMax came up with a brand new 2-stroke engine design in which they managed to reduce the fuel consumption by up to 20% while simultaneously increasing power output. They called these engines “Strato Charged”, which was basically their trademarked name for a new scavenging system. Strato Charge 2-stroke motors are capable of generating more torque at lower RPMs, which widens the effective power band of the engine.
It also reduces environmental footprint while increasing the amount of runtime you get from a tank of gas. When Husqvarna purchased RedMax in 2007, they also acquired their technology and incorporated Strato Charge into their chainsaw engines under the name of “X-Torq”. The X-Torq engines used in next generation Mark II chainsaws are based on the original Strato Charge scavenging technology, with quite a few optimizations to further improve efficiency and power output over the original design.
The way this works is, a fresh charge of air is sucked into the carburetor through a secondary butterfly valve located next to the main valve which supplies the fuel-air mix. This fresh charge of oxygen rich air is used to create a “buffer” between the outgoing exhaust gases and the incoming fuel-air mix, to prevent fresh charge from getting dumped into the exhaust channel along with the outgoing gases. The oxygen in this fresh air charge also helps burn off any half combusted fuel particles in the exhaust, before these gases reach the muffler. To understand more about 2-stroke engines, read : 2-stroke vs 4-stroke engines : What’s the difference?
VIDEO | Husqvarna (left) Air Injection vs STIHL (right)
On standard 2-stroke engines, some of the incoming fresh air-fuel mix is always lost alongside the exhaust gases since both the intake and exhaust ports are open together for a small window of time. The incoming air-fuel mix from the crankcase is what drives out the exhaust gases, and some of it is dumped outside in this process. X-Torq technology uses a combination of factors to mitigate the efficiency losses-
- A brand new scavenging system that uses a stream of fresh air to drive out the exhaust gases
- Hemispherical combustion chamber for higher power output
- Improved carburetor design for better acceleration
- 2-ring piston to hold compression better and increase power output
- Improved cooling fin design for better heat dissipation
Stihl has their own version of this technology called “2-Mix”, in which they use stratified scavenging to create a barrier of fresh oxygen rich air between the outgoing burnt gases and incoming fuel mix. They are also able to match Husqvarna’s X-Torq efficiency improvements with up to 20 percent reduction in fuel consumption and much lower exhaust emissions compared to standard 2-stroke engines.
Lower emissions and better fuel efficiency are just some of the advantages you get with stratified charging, performance is also improved since the power band of a 2-stroke engine is much narrower compared to that of a 4-stroke engine. And by increasing the torque at lower RPMs, X-Torq also increases the “grunt” of your chainsaw while it is cutting through a thick log of wood, so it doesn’t bog down or stall. All this is achieved without any increase in the total number of moving components, or weight of the engine.
Air injection uses cyclonic separation to prevent large debris from clogging up your chainsaw’s air filter. This works very much like a centrifuge, or a bagless Dyson vacuum cleaner. The spinning flywheel in the starter assembly has an array of specially designed cooling fins on it. When the engine is running, this cooling system sucks in fresh air from outside, and spins it around like a miniature tornado within the starter housing. Centrifugal forces act on all the sawdust and sand within this air, and the heaviest particles are thrown away the farthest while the smaller, lighter particles stay closer to the center of the flywheel.
There is a pre-separator duct which gathers up all the clean air containing these smaller particles and sends them to the air filter which is located on top of the carburetor. This way, you ensure that no large debris is sent to the air filter which ensures longer filter life and superior performance since the carburetor is getting a steady supply of clean air even in the dirtiest of operating conditions. Meanwhile, all of the large saw chips spinning around in the cyclone are chucked out of the chainsaw through a dedicated outlet duct.
Stihl was a little late to incorporate this technology into their heavy duty saws, but they have finally caught up with their own version of cyclonic separation which is used in the MS 261, MS 271, MS 291, and MS441. Stihl calls their version the “long-life air filtration system”, and they use cyclonic separation in conjunction with large fabric filters in their professional saws for maximum durability on jobsites.
Comparison — Husqvarna 120 Mark II and Stihl MS 170
People often used to compare the Husqvarna 240 with the Stihl MS 170, since they rival each other in the segment of 30cc homeowner saws. Stihl has the advantage in the weight department, weighing in at just 4 kilos or 8.8 lbs. dry with no cutting equipment attached. The 120 Mark II which can be considered as the successor to the 240, weighs just about 10.7 lbs. dry. It is slightly heavier than the 240 which weighs 10.3 pounds, but that extra weight goes towards a larger fuel tank. While the 240 has a 0.14 US pint gas tank, the 120 Mark II can hold up to 0.59 pints of fuel. This, in combination with the improved X-Torq engine results in more run-time for cutting firewood.
The Stihl MS 170 on the other hand, has a slightly smaller tank at 0.52 US pints or 250cc. And it is slightly behind on power as well, with 1.7hp compared to the 1.88hp of the 120 Mark II. The MS 170 also lacks a centrifugal air cleaning system like Husqvarna’s Air Injection, even though Stihl has implemented their long life air filtration systems on higher end models starting with the MS 261. Husqvarna has perfected this cyclonic debris separation technology and implement it even on their entry level homeowner models such as the 240 and 120 Mark II. Basically, it means the air filter on the 120 Mark II will require less frequent cleaning and the chainsaw itself can endure harsher environments compared to the Stihl MS 170.
Both the MS 170 and 120 Mark II can be equipped with 3/8” pitch 16” low kickback bar and chain, and they have all the necessary safety features (inertial chain brake, chain catcher, throttle lock off). The MS 170 is equipped with a special microprocessor controlled carburetor, which adjusts the air fuel ratio by tuning the carburetor jets mid operation based on data readings from sensors. These sensors detect any restrictions in airflow and adjust fuel flow accordingly, to maintain steady engine rpm. This feature does come in handy, since the Stihl MS 170 is more likely to get its air filter clogged compared to the Husqvarna 120 Mark II which has a cyclonic dust separator system (Air Injection). Husqvarna also has intelligent self-tuning carburetor technology, but they use it on their premium grade chainsaw models.
So which chainsaw should you buy? Our personal choice is the Husqvarna 120 Mark II for the following reasons :
- It is more powerful (1.88 hp vs 1.7 hp)
- It runs longer on each tank of gas (0.59 pint gas tank vs 0.52 pint gas tank, also the 120 Mark II has a X-Torq engine)
- It requires less maintenance due to the Air Injection centrifugal cleaning system which keeps the air filter relatively clean for longer periods of time
- It is more readily available online, so you are more likely to find lucrative deals and discounts (Stihl uses licensed dealers to distribute their products through physical stores)
Stihl fans will say that their company hasn’t sold out to big box stores, which means they haven’t compromised on build quality to fulfill production volume demands. But with modern manufacturing technology, that statement simply does not hold true. We have verified through various sources and consumer reviews that Husqvarna chainsaws are just as well built as their Stihl counterparts, and in the end it all comes down to your personal preference. Both of them manufacture excellent chainsaws, but Husqvarna saws are easier to purchase simply because they are more readily available online. You can still purchase Husqvarna’s from traditional brick and mortar dealerships, if you want a close up inspection of the chainsaw and a live demonstration.
Review : Husqvarna 135 Mark II — Gas Chainsaw
- Inertia chain brake
- Combined choke/stop control allow for easier starting and reduce the risk of engine flooding.
- Chain tensioning from the side : Allows quick and convenient chain tensioning.
- Fuel pump designed for easy starting.
- LowVib : Effective anti-vibration dampeners absorb vibration, sparing the user’s arms and hands.
- X-Torq : Deliver lower fuel consumption and reduced exhaust emission levels in accordance with the world´s most stringent environmental regulations.
- Air Injection : Centrifugal air cleaning system for reduced wear and longer operating time between filter cleanings.
It costs slightly more than the 120 Mark II, but also packs more power along with a larger gas tank. The 135 Mark II, surprisingly weighs less than the 120 Mark II at just 10.36 pounds for the powerhead, even with a larger tank. Both use a 38.2cc X-Torq engine, but the one in the 135 Mark II has been tuned up to produce 2.1hp which helps when you are going through thicker logs. It packs all the power as you could possibly require from a 16” homeowner saw, and the impressive power to weight ratio makes this a nice prospect for a prosumer saw if you want something small for limbing trees after you fell them with a larger saw.
Husqvarna 135 Mark II vs Husqvarna 120 Mark II
The 135 Mark II should also excel at post storm cleanup tasks, since it is so maneuverable and lightweight despite packing some serious punch. The chain speed is 55ft/s, quite similar to the 120 Mark II and with its increased power this saw should never bog down even when you’re going through a 16” log of cherry or oak. You can use it to fell trees, but we wouldn’t recommend that you try taking on anything taller than 30 feet with the 135 Mark II. It comes with all the standard Husqvarna tech – X-Torq engine, Air Injection centrifugal air filtration, and LowVib vibration dampening for comfortable operation. T
he side mounted chain tensioner should allow you to tighten your chainsaw chain quite easily. Check up our article on how to tighten your chainsaw chain to learn more about the proper amount of tension you should have in the chain while cutting wood. The 135 Mark II also features an inertia activated chain brake for operator safety, and a combined choke/ stop control for easier startups.
Next generation 50cc chainsaws —
Husqvarna 545 Mark II and 550 XP Mark II
✓ Read the official press release announcing these next generation chainsaws.
✓ Designed to deliver exceptional cutting capacity for handling small and mid-sized trees.
Common Features : 545 (545 G) Mark II — 550 XP Mark II (& 550 XP G)
- Two felling sights, one vertical and one horizontal – both are molded into the plastic for clear aiming and permanent guidance.
- Ergonomic handles provide a safe, comfortable grip
- Cooling capacity improved by 13% (compared to previous generation Husqvarna 50cc chainsaws.
- Four key improvements :
- Optimized airflow
- Increased cooling fins in critical areas that contribute to more effective cylinder heat dissipationI
- Insulating heat shield, specifically developed for the new chainsaws, which provide sealing against the cylinder area and minimizes heat leakage. This helps keep the carburetor compartment cool to improve starting in hot conditions
- Completely new muffler keeps temperatures down.
- Four key improvements :
- Redesigned air filter with higher capacity & improved sealing & an upgrade of the Air Injection system.
- well-balanced saw body with low gyroscopic forces provides excellent maneuverability and handling.
- Low Vib
- Air Injection
- X-Torq 50cc engine
Chainsaw features — HUSQVARNA 545 Mark II
Unique Features : 545 (545 G) Mark II
- Smart Start
- Heated handles and carburetor (only 545 G Mark II)
- Engine displacement 50.1 cm3
- Power output 2.7 kW
- Max chain speed 25.4 m/s
- Recommended bar length : 33-50 cm / 13”-20”
- Weight : 5.3 kg / 5.5 kg (excluding cutting equipment)
Unique Features : 550 XP Mark II (& 550 XP G)
- Heated handles and carburetor (only 550 XP G Mark II)
- Magnesium crankcase
- Adjustable oil pump
- Visible fuel level
- Engine displacement : 50.1 cc
- Power output : 3.0 kW
- Chain speed at 133% of peak power rpm : 26,1 m/s
- Recommended bar length : 33-50 cm / 13”-20”
- Weight 5.3 / 5.5 kg (excluding cutting equipment)
Earlier this year in January, Husqvarna announced their next generation of 50cc prosumer chainsaws. These are designed completely from the ground up, with a focus on delivering the ultimate in performance, reliability, and efficiency. X-Torq and Air Injection have been optimized even further than before, with feedback from professional loggers and thousands of hours of internal testing aided by digitalization. All the vital components are brand new, and the overall design is intended to be as sleek as possible while retaining the level of functionality you would expect from a professional grade chainsaw. Husqvarna made sure to only add what is functional, instead of throwing in a bunch of stuff just because they can which would result in a chainsaw that feels bloated and clunky.
VIDEO | See the Launch of the 550 XP Mark II in Australia
Husqvarna focused on 3 things while making the 550 XP Mark II and 545 Mark II :
- High power output and immediate acceleration
- Maneuverability and productivity
- Versatile performance and the ability to fell trees rapidly in any climate
These 2 chainsaws will act as the foundation for many new models of prosumer chainsaws going forward. Development was aided with sensor based data collection and digital prototyping. Husqvarna has tried to minimize all possible gyroscopic forces that come into play when you’re operating the chainsaw, these forces are generated by the spinning/oscillating masses such as flywheels, crankshafts, clutches, chains, etc. They have also installed a brand new air filter system with superior airflow capacity and better sealing to prevent debris from getting into the carburetor.
Cooling capacities for both the 550 XP Mark II and 545 Mark II have been improved by 13% over the previous generation models, thanks to more cooling fins placed in strategic locations around the cylinder and crankcase. Airflow paths have also been redesigned for better engine cooling, and a heat shield has been installed between the cylinder and carburetor chamber which prevents heat leakage.
VIDEO | Under the Hood — 545 Mark II
This heat shield also helps cool the carburetor, which comes in handy if you’re working on a hot day in a place like Arizona. For the 2nd generation models, Husqvarna has completely redesigned the muffler as well. This is to reduce noise levels and meet global noise pollution regulations. Air Injection has also been upgraded, which results in cleaner air filters and consistent power output even in the dustiest of work environments.
Husqvarna has equipped both the 550 XP Mark II and 545 Mark II with an improved version of their carburetor Auto Tune system which automatically detects changes in air flow and modulates the fuel supply to keep engine rpm steady.
Auto Tune uses sensors and a microprocessor to detect changes in altitude, temperature, fuel types, and airflow (from a clogged air filter). Based on these parameters, the chip will adjust the carburetor for maximum efficiency and performance. The old Auto Tune was pretty good, but Husqvarna has updated the sensors and firmware for the new generation so they can process changes in the work environment and adjust at a much faster rate.
VIDEO | A Closer Look — 550 XP Mark II
Apart from updated X-Torq, Air Injection, and Auto Tune, the Mark II series of chainsaws has seen ergonomic changes along with a few smaller tweaks here and there. For instance, the 550 XP Mark II no longer has a decompressor and the front handle has been redesigned to give you extra room between your hand and the top cover. It may not seem like much, but for someone who is 6’6” and wearing thick work gloves this redesigned front handle is a massive improvement since it gives your front hand and wrist so much more freedom. The front handle has also been shifted forward by about 10mm, which makes the 550 XP Mark II feel less cramped compared to its 1st gen predecessor and this allows for a more positive grip.
The Mark II saws also have new air channels which blow air over the crankcase and under the exhaust for better cooling, and that is a nice thing because you’ll be able to run these saws for longer thanks to their larger fuel and oil tanks compared to 1st gen models. The next generation saws also sport brand new bars and chains. Husqvarna have designed a new X-Force bar that is lighter and tougher than the last one, and the new X-Cut SP33G chain is an option (not included in the box by default). The 550 XP G Mark II and 545 G Mark II have heated handles and carburetors for working in extremely cold temperatures.