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How Does a Gas-Powered Chainsaw Work? (+ Review of 5 TOP Rated Picks)

A gas-powered chainsaw can fell a small forest of mature trees in a matter of hours. At home, it is useful for trimming overgrown tree branches and brush and cutting firewood. It is a mean wood cutting tool that simplifies an otherwise physically demanding, time-consuming, and potentially dangerous task. 

Compared to manual cutting tools, a gas-powered chainsaw does the job ridiculously fast and far more efficiently. So much that watching an experienced lumberjack dexterously cut up a large tree makes using a chainsaw seem easy. Is it though?

To put it mildly, a chainsaw is a dangerous tool to an inexperienced pair of hands. Before pulling the cord to rev the gasoline engine to life, you must first know how to use a chainsaw safely. As it happens, that’s the topic of this article. 

This article will introduce you to gas-powered chainsaws, explain how they work, and educate you on how you can use yours safely. Later, we will discuss what features you should look for in a gas chainsaw before reviewing our picks for the best gas-powered chainsaws.

What is a Gas-Powered Chainsaw?

Makita EA6100PRGG 20

A gas-powered chainsaw uses a two-stroke combustion engine to power a fast rotating wood cutting chain. It differs from electric chainsaws that use an electric motor to spin the cutting chain. For their power and smoother cuts, gas chainsaws are the preferred option for the heavier wood cutting tasks.

A chainsaw, in the most basic explanation, is a mechanical tool that uses a chain with sharp teeth to cut through wood. The chain is spun around a guide bar, cutting through wood as it rotates. The length of the guide bar determines how thick a tree the chainsaw can cut.

Gas-powered chainsaws can be classified into three categories based on their sizes, namely homeowner, farm and ranch, and professional chainsaws. 

Homeowner chainsaws are the smallest type, with a maximum bar length of 18 inches. These chainsaws are brought out occasionally to cut firewood and overgrown tree branches in the backyard.

Less powerful and with a slimmer body, homeowner chainsaws are designed to be easier to handle and use. Because they are small and lack some features, these chainsaws are the most affordable you can find.

Next in terms of size are farm and ranch chainsaws. As the name suggests, you will typically find these on a farm or ranch. With a maximum guide bar length of 24 inches, these chainsaws have more advanced features like vibration dampening systems and spring-assisted starters. 

With more horsepower than homeowner chainsaws, farm and ranch chainsaws make light work of cutting fencing poles and clearing trees for new farmland. They also see more active service than homeowner chainsaws.

The largest type is professional gas chainsaws that foresters and journeyman loggers use to cut down trees that will be sawn into lumber. These chainsaws are larger and a lot more powerful than the previous two types. 

Because of their weight and power, professional chainsaws have a top handle that enhances comfort and safety. In fact, everything is larger on these chainsaws, including the fuel tank, guide bar, and rev count per minute. As such, they are the best option for cutting large trees.

The larger size, power, and advanced features of professional gas-powered chainsaws make them considerably more expensive. Invest in one if you cut a lot of firewood or regularly have to bring down large trees.

When Was the First Gas-Powered Chainsaw Made?

The first gasoline-powered chainsaw was developed by Emil Lerp in 1927. However, credit for the idea of a powered chainsaw for cutting wood goes to German mechanical engineer Andreas Stihl who registered the patent for the first electric chainsaw in 1926. 

Stihl would develop his own version of a gasoline chainsaw in 1929. It must be said still that Stihl’s idea for the chainsaw wasn’t an original one. The design can actually be traced almost a century back to 1830 when another German, physicist and bone specialist Bernhard Heine developed the osteotome.

The osteotome, which translates to ‘bone cutter’ was used in surgery to cut bones. It was a revolutionary piece of medical equipment that replaced the crude tools that had been in use until then. The osteotome looked like a miniature version of the chainsaws of today. The only differences are it was hand-powered and was used to cut bone instead of wood.

Between the osteotome and Stihl’s first electric-powered chainsaw were numerous attempts at a chainsaw that could be used for logging purposes. One was the Hamilton saw that featured a large chainsaw hand-cranked by two men. Quite a few, notably John Muir’s that had a blade-guided chainsaw, weighed too much to be commercially viable.

Gas Chainsaws Vs Electric Chainsaws

Gasoline chainsaws have been the standard wood cutting tool for generations. But of late we have been seeing more battery-powered models come to market. Thanks to the energy-dense and lighter li-ion batteries, these chain saws cut just as fast as their gas-powered cousins. But just how do electric chainsaws stack up?

One major drawback of gas-powered chainsaws is the noise they make. While they will make light work of tree stumps in the backyard and any branches that may be hanging precariously over your roof, they are too noisy for a residential setting. Electric chainsaws, on the other hand, hardly make a sound.

Another attraction for electric chainsaws – both the corded and battery-powered models – is they don’t produce any fumes. You could, if need be, use them indoors without worrying about carbon monoxide poisoning. Unfortunately, the opposite is true with gas chainsaws.

In terms of raw power, however, electric chainsaws are no match for gasoline chain saws. Their power and mobility make gas chainsaws the perfect wood cutting tool for lumberjacks, arborists, and foresters.

However, all that power does make gas chainsaws harder to control. Unless you are an experienced user, these heavy wood cutting machines could hurt you. You could also say that power cords for electric chainsaws can pose a tripping risk, especially in a wooded area where it’s easy to get tangled up.

For any large tree-cutting jobs away from residential neighborhoods where you don’t have to worry about making a racket and there’s enough ventilation, a gasoline chainsaw will get the job done the fastest. All you need is the fuel to refill the tank as needed, unlike electric chainsaws that would require a long cable to access AC power.

Gas-Powered Chainsaw Buying Guide

Makita EA6100PRGG 20″ 61 cc Chain Saw

How Gasoline Chainsaws Work

Other articles have done a better job explaining how a 2-stroke engine works. We will explain it in the context of a gas chainsaw. The chain assembly – the actual cutting chain and the guide bar – is the apparatus that does the actual cutting. 

The chain has sharp teeth that cut into wood when it spins rapidly around the guide bar, hence the name ‘chainsaw’. The gasoline engine is what generates the spinning force that enables cutting. How the engine works is that inside the cylinder is a mechanism that burns gasoline and releases the energy that pushes a piston back and forth.

That back and forth motion of the piston has to be converted to a rotary motion that then spins the cutting chain. That is accomplished by a connecting rod and crank system. Now, if chainsaws worked like this it would mean the blade runs continuously, as long as the engine is running. That wastes energy and would cause numerous injuries.

Instead of the chainsaw running continuously, a centrifugal clutch ensures the cutting chain spins only when you throttle or rev up the engine but is otherwise idle. The clutch, in this case, is a switch that connects the engine with the cutting chain. It, in effect, stops the chain from spinning without necessarily switching off the engine.

Transferring the power from the clutch to the chain is a series of gears that connect with the sprocket. The sprocket and the guide bar have teeth that are perfectly aligned so that when the clutch is engaged, the whole chain spins. With each revolution around the sprocket and chain assembly, the chain saws into the wood.

Now that you have a basic understanding of how a gasoline chain saw works, let’s move on to how you operate one.

How to Start a Gas Chainsaw?

Electric chainsaws are easy to start. A simple flick of a switch will have the motor spinning and the chainsaw ready to go. On the other hand, there is nothing straightforward about how to start gas chainsaws. 

Starting a gasoline-powered chainsaw isn’t just a matter of pulling the cord. Some steps must precede this step. Even when it comes time to pull the cord, the chainsaw hardly starts on the first try.

The steps to follow when starting a gasoline chainsaw will seem over-elaborate, but they are for your safety. Here is the right way to do it:

  1. Place the chainsaw on level ground to stabilize it. While the tool is on the ground, check the fuel level and make sure the chain is well lubricated and tensioned. Ensure there aren’t any obstacles and that there are no people or pets close to the chainsaw.
  2. Place your right foot in the rear handle. This ensures the chainsaw remains stable while you pull the starting cord. Check to see that the chain brake is engaged so the chain doesn’t spin before you are ready to start cutting.
  3. Turn on the choke. The choke controls the air-fuel mixture and opening it will supply a richer mixture of air and fuel to the engine. Some chainsaws will not have it, but if yours has one, press the fuel primer to push fuel into the carburetor.
  4. While holding down the chainsaw with one hand, pull the starting cord with your other hand. You may need a full pull before the engine starts. Once it starts, move the choke to the run position.
  5. Test the chain brake before you start cutting. In fact, give the chainsaw a few minutes to run before you start cutting. To test the chain brake, release it for a few seconds and re-engage it. Do it again to be sure it will stop the chain from spinning when you need it to. You are now ready to start cutting.

The steps we have discussed above are mainly intended to prevent injuries. But gas chainsaw safety does not stop there. Below we discuss a few more safety tips:

How to Use Gas-Powered Chainsaws Safely

It’s been said that among the tools that do not require a license to operate, chainsaws are up there with the most dangerous.  It is hardly surprising when you consider the tool’s raw power and the exposed cutting blade.

In case this is the only article you will read before taking your new gas chainsaw for a spin, the following tips will ensure you don’t harm yourself in the process.

  • Make sure you are never far away from help

Again, this seems like we are exaggerating the safety risk of using a chainsaw. But when chainsaw accidents happen they are usually serious. Most cuts are deep and can result in rapid blood loss, with fatal consequences. 

To start, stay away from any chainsaw if you are not sober. You will not only harm yourself and others but will damage property, too.

If you are a beginner chainsaw user, never go out on any tree-cutting errand with a chainsaw alone. Make sure someone is accompanying you. That second person will make sure you receive urgent medical help in the event of an accident.

  • Wear the right safety clothing

Avoid wearing loose-fitting clothing when operating a chainsaw. Anything that can catch on the chainsaw’s teeth is an injury risk. Make sure your clothes fit snugly.

Just as dangerous is long hair that dangles on the chainsaw blade as you work. Tie your hair back and always wear a helmet with a face shield to protect yourself from kickback. Your boots, too, should be fully protective, with steel toes. 

To protect your legs and hands, always wear chaps and the right type of gloves. Finally, gas chainsaws are extremely loud tools, so protect your hearing with earplugs.

  • Maintain the right posture

You want to make sure your feet are firmly planted on the ground before you start cutting. With your legs parted for maximum balance, always hold the chainsaw with your two hands. To maintain the right posture as you cut, never cut from a ladder. Also, never cut anything from higher than your shoulder.

To prevent kickback, hold the chainsaw slightly to your side. If possible, cut at an angle. That way, any kickback isn’t directly at you. Last but not least, scan your surroundings to make sure the tree does not fall directly on a building, over power lines, across the road, or on you. 

It shouldn’t come as a surprise to you that the tree is falling a certain way. You will be surprised how many accidents happen as a result of people not thinking ahead when felling trees. 

  • Inspect and prep your chainsaw before cutting

It’s improper to just yank your chainsaw from storage and proceed to use it without inspecting it. When you inspect it, you should check to see if the chain brake is working properly. 

More importantly, the chain must be tightly tensioned and lubricated. A loose and unlubricated cutting chain is an accident waiting to happen. Lastly, replace blunt cutting chains as they waste energy and often cause accidents.

What to Consider When Buying a Gas-Powered Chainsaw

There is no question about it; there are tree-cutting jobs for which gas-powered chainsaws are the only way to go. You’ve probably read it too many times but, yes, build quality is important. And as long as you stick with the leading brands, you will be fine.

We felt we should get into a little more detail about the safety features you have to insist on. Mercifully, most of these features are now standard with the major chainsaw brands. But you won’t know how to prioritize them if we don’t highlight them.

  • Horsepower

Horsepower determines a chainsaw’s torque or power. Engine power is measured in cubic centimeters (cc) and, for chainsaws, ranges between 31 and 65 cc. 

Choose a chainsaw that matches the woodcutting task. For tougher and larger trees, a 65cc, professional-grade gas chainsaw will be most ideal but it will be harder to operate. Safety-wise, a more powerful chainsaw is harder to control.

  • Chain brake

A chain brake allows you to lock the chain and stop it from spinning, usually when the chainsaw is idle. It also helps to prevent injuries caused by kickback. Manual chain brakes engage by consequence of the handguard pushing back against your wrist. Inertia-activated chain brakes, which are better, engage automatically when the chainsaw senses kickback.

  • Bucking spikes

Bucking spikes are the metal spikes that you see at the base of the chainsaw, connected to the tool’s body. As do chain brakes, bucking spikes will help protect you from kickback by anchoring your chainsaw on the trunk of the tree you are cutting. 

Bucking spikes are especially helpful on cutting jobs where you may struggle to hold the chainsaw still. In the same way, they will help you make straight cuts.

  • Automatic chain oiler

Faced with a lot of cutting work, it is easy to put off oiling the chain or neglect it entirely. The chain wears out faster and may break due to overheating, causing injuries. 

An automatic oiler ensures the chain stays lubricated and cooled and allows you to concentrate on the cutting task. Some automatic oilers also can adjust oil flow depending on the cutting task at hand.

  • Tool-free chain adjuster

A hand-turned chain adjuster removes the need for a scrench, which is a wrench/screwdriver tool used to manually adjust the tension on the cutting chain. If forced to use a tool, many will neglect to properly tension the chain. Chains loosen with use and will eventually slip out if not tensioned, which can cause injuries.

Review of the 5 Best Gas-Powered Chainsaws

Below we review the best gas chainsaws in 2021. We will start with our picks for the best chainsaws for home use and work our way up to the professional-grade options. Let’s get shopping!

1. Husqvarna 120 II 16″ Gas Chainsaws

If you are looking for a gas chainsaw for occasional tree trimming and wood cutting work around the homestead, the Husqvarna 120 II is a worthy option. With a small to mid-sized 16 inch blade, the chainsaw works out of the box.

Husqvarna made sure to include the most essential safety features on this chainsaw. These include a built-in safety brake and an automatic oiler that ensures the chain stays lubricated to prevent it from breaking.

Once in a while, you will use the saw for heavier cutting jobs. At such times, you will appreciate the tool’s LowVib system that lowers vibration, reducing operator fatigue. The chainsaw’s compact size also helps limit fatigue on longer cutting jobs.

While a few users have complained about the chainsaw stalling when cutting hardwoods, they also say it does start again, albeit with more than one try at times. From the testimonies of other reviewers, it may be down to the quality of the fuel and not necessarily the tool itself. The fuel is 2-cycle, which is a mixture of oil and gas, not regular gas.


Husqvarna 120 II 16″ Gas Chainsaws


  • Compact size reduces operator fatigue
  • Air cleaning system improves engine life
  • Low vibration springs reduce operator fatigue
  • Durable build quality


  • Tends to stall when cutting thicker, harder wood.

2. CRAFTSMAN 42cc-16 (2020 Model) S165 42cc Full Crank 2-Cycle Gas Chainsaw

Another solid contender for the best gas chainsaw for home use in 2021, this Craftsman 42 cc 16-inch chainsaw has more-than-average power for its size. It will tear through brush and small branches with ease. 

Unfortunately, a common complaint with this chainsaw is that it can be difficult to start. That is surprising because this chainsaw supposedly employs an ‘Easy Start Technology’.

That other reviewers report no issues with starting the chainsaw does suggest one needs to follow the instructions more carefully. That includes using the right fuel/oil mixture and lubricating oil and warming the engine by pulling the starting cord up to five times and pushing the choke all the way before starting. The engine should fire right up.

Safety-wise, we like that the chainsaw has an automatic oiler with a flow rate that you can manually adjust. For extra protection against kickbacks, the safety chain brake is inertia-activated and not manual. 

In terms of comfort, the cushioned full-wrap aluminum handle caught our eye. So does the 3-point anti-vibration system that makes it easy to maneuver the chainsaw. On the other hand, the bucking spikes ensure you maintain a firm grip on the saw for more controlled cutting. You will also love the no-tool access for the spark plug and air filter.


CRAFTSMAN 42cc-16 (2020 Model)


  • Plenty of torque for standard wood cutting tasks
  • A low kickback blade improves safety
  • An anti-vibration system and comfortable handling reduces operator fatigue
  • Affordably priced


  • Oil tends to leak when the chainsaw is in storage case
  • The cutting chain could have been sharper

3. WEMARS Gas Chainsaw 52cc 18 Inch Power Chain Saw

Looking for an affordable gasoline chain saw that holds up well for the semi-professional cutting jobs? With an engine displacement of 52 cc and a razor-sharp blade, the Wemars gas-powered chainsaw with an 18-inch blade will cut through regular wood like it’s a stick of butter.

You will need to warm the chainsaw well when you first start it. There are quite comprehensive instructions on how to do that on the product’s Amazon listing. Once warmed up, the tool starts without issues. 

Noting challenges others have had starting the saw, some reviewers on Amazon helpfully chipped in with tips. One concerns the choke. Spraying a reasonable amount of lithium grease on the internal choke mechanism will ensure it isn’t stiff. However, you will have to remove the air filter cover to access it, which you should not attempt if unsure.

When breaking in the chain, some suggest using a 40-1 fuel/oil mixture and then reverting to the normal 50-1. As far as safety features go, an automatic oiler keeps the chain well-lubricated while the cushioned front and back anti-vibration handles improve both comfort and safety.


WEMARS Gas Chainsaw 52cc 18 Inch


  • Ample power for heavier cutting tasks
  • Too-free, easy-release air filter makes it a breeze to replace and clean
  • Automatic chain lubrication system protects chain from overheating and breaking
  • Integrated chain brake prevents injuries from kickbacks
  • Great price


  • The choke has design issues that make starting the chainsaw difficult

4. Makita EA6100PRGG 20″ 61 cc Chain Saw

From the impressions of people who have bought the chainsaw on Amazon, this Makita EA6100PRGG, 61 cc gas chainsaw seems to justify its high price. By how much, it is always hard to tell. To be fair, this saw feels well-built, with terrific power. Made of magnesium, the motor housing is lightweight yet durable. 

We also noted the saw’s blazingly fast acceleration that, with the sharp blade, delivers cleaner, more precise cuts. Many feel that counts for nothing if the chainsaw is a pain to start. That concern is addressed by the spring-assisted starter mechanism that ensures quicker starts with less pulling force.

For your safety, the chainsaw has such features as an inertia-triggered chain brake, a touch & stop single lever control that shuts off the engine with just a touch, and an advanced vibration dampening system that reduces operator fatigue and ensures you stay alert for your safety.

For the power the 4.6hp engine produces you will rightly worry about how much fuel you will be using. The manufacturer thought about that too and innovated the Stratified Air Scavenging engine that, apart from delivering above-standard fuel efficiency, produces significantly low emissions. 


Makita EA6100PRGG 20″ 61 cc Chainsaw


  • Beastly power that will make light work of most wood cutting tasks
  • Heavy-duty cartridge air filter system that extends filter life.
  • Compact and lightweight design reduces fatigue on long cutting jobs
  • Lateral chain tensioning makes chain adjustment easy
  • Floating rim sprocket makes maintenance easy and
  • Easy-to-clean chain compartment that helps to clear chips and improve chain life


  • Expensive


5. DEREAL 62cc-Gas-Chainsaw 2 Cycle, Gasoline-Powered

Gasoline-powered chainsaws get more expensive the higher you go on the torque scales. For its power and range of safety features, the Dereal 62 cc gas chainsaw’s price can’t be beat. Well built with a 20-inch blade, this saw will take a workout. It suits a semi-professional user who has to regularly cut down large trees and process limbs for firewood.

Don’t let the many plastic parts deceive you, once you use it you will discover the chainsaw has quite a rugged build. As long as you use the correct fuel/oil mixing ratio, the chainsaw works right out of the box. 

We always stress safety features on our chainsaw reviews and for that this Dereal does impress. We like the dual throttle switches that you have to press together for the tool to start. That feature prevents accidental starting, which is known to cause injuries. 

We also dig the non-slip, shock-absorbing handle that reduces operator fatigue, which is also a common cause of injuries. As well as prevent the chain from jamming and breaking, the automatic oiler on this chainsaw will ensure the chain does not wear out too fast.

The low price is an indication that this isn’t the strongest chainsaw out there. But chainsaw durability is as much about build quality as it is about quality of care and maintenance. As long as you keep it out of the rain, steer well clear of poor quality oil, and don’t throw it around recklessly, you should get years of faithful service out of this chainsaw.


DEREAL 62cc-Gas-Chainsaw 2 Cycle Gasoline


  • Affordable
  • Plenty of torque for semi-professional logging
  • Dual-throttle system improves safety
  • Lightweight reduces operator fatigue
  • Non-slip, shock-absorbing handle design enhances handling
  • Updated engine improves fuel efficiency


  • Too many plastic parts cheapen the tool’s quality


Do you have a question about gasoline chainsaws that we haven’t addressed? Below we answer more questions most frequently asked about gas chainsaws:

What should I look for in a gas chainsaw?

A gas chainsaw can be a pain to start, so a spring-assisted starter will help greatly. And to make sure the chainsaw works for your needs, consider the torque and guide bar length. But safety should be the top priority, and features like an automatic chain brake, bucking spikes, and an automatic chain oiler are must-haves.

Are gas chainsaws better than electric?

It depends on what you intend to use the chainsaw for. Low on noise, electric chainsaws have just the right amount of power and will work well for cutting tasks in a residential setting. For heavier, professional cutting jobs away from habited areas, gasoline-powered chainsaws are more powerful and by far the best option.

What is a good size chainsaw?

A good size chainsaw is what you can use safely and will help you accomplish your wood cutting task efficiently. Generally, the blade should be at least 2 inches longer than the thickness of the tree you plan to cut.

What is considered a powerful chainsaw?

Chainsaw power is measured by the engine displacement. For most cutting and pruning tasks, the chainsaw must have at least 24cc of torque. The professional-grade saws, however, produce as much as 62 cc, which is really powerful. Note, though, the more powerful a chainsaw is, the heavier and harder to control it usually is.

Final Word

We hope you now have a clearer understanding of how gasoline-powered chainsaws work and what to prioritize when shopping for one. We are also confident that among our picks should be one that meets your needs. 

As always, when using chainsaws, safety first.