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Are Chainsaws 2-stroke? Tips from a professional

People planning to purchase a new chainsaw often ask me what type of gas engine they should go for? They know that a lot of newer small gas engines use four strokes. But they do not see a lot of 4 stroke chainsaws.

Are chainsaws 2-stroke?

Most of the gas chainsaws you’ll find today are 2-stroke. A few brands, like STIHL, started to offer chainsaws with four-stroke engines. But these are mostly heavier professional models. Generally, four-stroke engines can deliver more power but are heavier, and a two-stroke engine has fewer components and is easier to fix.

In this blog article, I will further answer the question if chainsaws are using a 2-stroke engine. And look into the advantages and disadvantages. I will also answer some of the frequently asked questions that I get about 2 and 4 stroke chainsaws.

Are Chainsaws 2-stroke?

Chainsaw engines are either 2-stroke or 4-stroke. In some cases, they are referred to as 2-cycle or 4-cycle engines. Whether cycle or strokes, they all mean the same thing. In a 2-stroke engine, power is produced every time there are two strokes on the pistons, and for a 4-stroke engine, four strokes on the piston are required to produce power.

The third stroke in a 4-stroke engine requires an oil reservoir from which it’d take oil to lubricate the engine. This is why 4-stroke engines are built with a separate reservoir for oil, and you won’t need to mix the oil with petrol for the engine to run.

On the other hand, this is not the case with 2-stroke engines. None of the strokes is dedicated to lubricating the engine, and the engine is not built with a separate reservoir. Therefore, you’ll need to mix the oil with petrol for the engine to run smoothly.

As mentioned earlier, almost all chainsaws are 2-stroke, and only a limited number of chainsaw brands offer 4-stroke engines. To better understand why we will look at the advantages and disadvantages of 2-stroke chainsaw engines over their 4-stroke counterparts.

● Advantages of 2-stroke chainsaw engines

Generally, 2-stroke engines are generally smaller and have fewer moving parts. This is an essential factor, not only for chainsaws but for other power tools. Since these tools are carried in your hands and used for hours, a lighter tool improves work efficiency. It also means that a 4-stroke engine is not as powerful as a 2-stroke engine of the same size.

The small size of 2-stroke chainsaws also makes them a better option, especially in cases where a bigger chainsaw will be more difficult to handle. For example, when cutting branches from a tree, you might need to climb and hold the chainsaw in one hand. In addition to increasing productivity, smaller chainsaws are easier to store, unlike the bigger ones that take up much space.

Another advantage of 2-stroke engines is that they can function even upside down or on their side. This is impossible with most 4-stroke engines because most oil systems depend on gravity to flow. Turning it upside down will only alter the flow of oil, which can cause a malfunction. The oil in 2-stroke engines is mixed with petrol and does not depend on gravity. Therefore, you can turn them anyhow you want, and they will still function properly.

You can see why 2-stroke chainsaw engines have certain advantages. You’ll want to have much flexibility when felling a tree, and with a 4-stroke engine, you’ll be more restricted.

As a 2-stoke engine has fewer moving parts, it is easier to maintain. This can be important if you do your maintenance yourself. They will also rev faster but have less torque at a lower speed.

Therefore, chainsaws are better with 2-stroke engines because:

  • Use upside down: They can function adequately when upside down or sideways, unlike 4-stroke engines
  • Better acceleration: They have higher acceleration and speed
  • Smaller / Leight weight: They are smaller and lightweight

● Disadvantages of 2-stroke chainsaw engines

In addition to the advantages I’ve pointed out above, 2-stroke engines also have a few disadvantages. The first is that they are generally louder than the 4-stroke counterparts, and this is why you should use ear protection when using a chainsaw. I have to say that I always recommend wearing ear protection when working with small gas engines, being 2 or 4-stroke.

Two-stroke engines also generate more smoke than four-stroke engines. Maintenance is another issue of concern with 2-stroke engines because you’ll need to clean the carburetor and spark plugs more often due to the presence of oil in the gas. However, this process is fast and won’t take much of your time.

The last disadvantage is that you’ll need to ensure that you maintain the correct oil/fuel ratio to avoid malfunction.

● Should I choose a 2-stroke or 4-stroke chainsaw?

From this, you can see that both two-stroke and four-stroke have advantages and disadvantages. Generally, for most people, 2-stoke chainsaws are still a better option, and that is why most brands are offering those. And there is only a limited number of 4-stoke options. Technology continues to get better, and the 2-stroke engines you’ll find today are more efficient and better than their predecessors. Of course, electric chainsaws are a third option that more and more users choose.

Frequently Asked Questions

We have gone through the advantages and disadvantages of 2-stroke engines for you to see why almost all chainsaws are 2-stroke. Now let us go through some frequently asked questions to enhance your understanding.

– Is a chainsaw 2-stroke or 4-stroke?

It’s rare to find a chainsaw with 4-stroke engines. As mentioned earlier, STIHL offers a chainsaw with a unique ‘hybrid’ engine with 4-strokes but functions like a 2-stroke. It still requires mixing or oil with petrol. This type of engine is generally called a 4-Mix engine, and it has a few advantages that make it better than 2-stroke engines. This includes improved fuel efficiency, less noise production, and lower emissions. STIHL chainsaws are a hybrid between 4-stroke and 2-stroke engines. But the disadvantage is that maintenance is more complicated, and they are not the cheapest models.

– What is the right ratio to mix oil and petrol in a 2-stroke chainsaw?

The appropriate ratio for most of the 2-stroke chainsaws you’ll find is 50:1. This implies that you’ll need to add 20 ml or 2.6 ounces of oil for every liter of petrol. However, the ratio can vary depending on the manufacturer of the chainsaw. Therefore, it’s best to always check the user manual for the appropriate ratio to use.

Alternatively, you can stick to buying pre-mixed. But generally, it’s more expensive than when you mix it yourself. However, purchasing pre-mixed fuel can be a good solution for people that do not like mixing, especially when you’re not sure of the right ratio to use.

– Can I use unmixed fuel on a 2-stroke chainsaw?

Never use unmixed fuel with your 2-stroke chainsaw. Doing this damages your engine within a short time. Oil helps to keep the pistons in the engine lubricated and keep them cooler. If you don’t add oil to the fuel, the pistons will continue grinding and eventually become completely scarred.

Friction will also increase, thereby generating an excessive amount of heat. The pistons will start to melt due to the excessive heat, and within a short time, they’ll stop moving.

– What’s the effect of adding too much oil to fuel?

The need to use the right mix ratio cannot be overemphasized, but the effect of adding too much oil to fuel is not as bad as not adding oil or less oil. Adding too much oil will reduce the performance of your chainsaw and cause it to release too much smoke. Eventually, your chainsaw will stop working, and this may happen faster if there is too much oil in the gas.

Another issue with adding too much oil is that it can cause your spark plug to start fouling, resulting in more frequent spark plug cleaning and eventually replacing it. If you’ve added too much oil and wondering how to fix it, the best way is to completely drain the fuel from your chainsaw tank and add fuel with the correct oil/petrol ratio. If you know that your gas tank is only partly filled, you can also add more gas to improve the oil gas ratio. But only do this if you know what you are doing. And if you used your chainsaw with a more oil mix, I recommend cleaning the spark plug before starting the chainsaw.

With everything in order, you can run the chainsaw for a few minutes to clear out the bad fuel mix that’s already in the fuel lines. Your chainsaw will be restored to its normal working condition and is ready to go.

– Are STIHL chainsaws 2-stroke?

STIHL chainsaws are generally 2-stroke chainsaws. But STIHL also has a unique 4-stroke chainsaw engine that works like a 2-stroke one. Even though they are a sort of 4-stoke, they still require mixing oil with petrol. The STIHL 4-stoke hybrid engine is called the 4-MIX engine.

– How do I make an oil and gas mix?

In addition to knowing the right ratio when mixing gas and oil, it’s also important to know the right way to make the mix. You’ll need a gas can to make it easier for you to measure the right volumes.

First, add the required amount of fuel into the can and carefully pour the right amount of oil. Close the gas can and shake it vigorously to ensure that the oil and fuel are adequately mixed. Depending on your preference, you can also add the oil to the gas can before adding petrol and shake.

Also, ensure that the gas you use is not too old. Old gas can go bad, and clog the carburetor. If you plan not to use the gas mix for some time (multiple months), I recommend adding some fuel stabilizer. When added, you can keep the gas for a much longer time.