How To Mix Chainsaw Gas And Oil In Your 2-Stroke Chainsaw Engine

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Have you ever had your chainsaw engine betray you and result in stop-start performance? If yes, then did you ever wonder if it could be due to mixing improper chainsaw gas? 

How to mix chainsaw gas and how much quality to mix are essential when using a chainsaw. Sometimes, people mix the chainsaw gas in the wrong ratio. You should always remember to have a fuel-to-oil ratio of 50:1 to get smooth performances. In this article, you’ll get to know all about how to mix chainsaw gas, which gas to mix, and other tips to keep in mind.

man mixing gas and oil in chainsaw

What is the difference between 2-stroke and 4-stroke chainsaw engines?

Before you get to know how to mix chainsaw gas, it is important to understand the difference between different types of chainsaw engines. Chainsaw engines come as either 2-strong versions or 4-stroke versions. Sometimes, the two are referred to as 2-cycle and 4-cycle engines. Without going too deep into the mechanics of chainsaw engines, a 2-stroke engine will produce power for every 2 strokes of the piston. Similarly, a 4-stroke engine will require 4 strokes of the piston for producing power.

In 4-stroke engines, for the third stroke, the oil will be taken from an oil reservoir and brought into the engine for lubricating it. These engines will have a separate oil reservoir and a specific stroke reserved for lubrication. This is why there will be no need of mixing oil into the gas that the chainsaw engine runs on.

In a 2-stroke engine, it doesn’t happen in the same way. In a 2-stroke engine, there is no separate oil reservoir. There is no separate stroke dedicated for lubrication of the engine. This is why, for keeping a 2-stroke engine running smoothly, you’ll need to add oil to the fuel.

Mixing gas and oil mixture for the chainsaws

There is no standard oil-to-gas ratio that works for every single in a chainsaw. You’ll need to check the user manual that comes with the chainsaw to know the ratio for your particular chainsaw. However, the majority of 2-stroke chainsaw engines and many other similar tools run on a fuel mixture that is one part oil to 50 parts gas, giving it the ratio of 1:50. Stihl, one of the biggest chainsaw manufacturers also recommends the use of a 1:50 oil-to-gas ratio.

However, many chainsaw engines also run on a mixture of ratio 1:40 while other ratios are also possible. This is why you should check the ratio in the manual, as using the wrong mixture could damage your chainsaw. 

Just to paint a better picture, a 1:50 ratio of oil-to-gas will work out to 2½ oz of oil to every gallon of gas. When you make the oil-and-gas mixture, you should make sure that you measure the amounts as precisely as you can. If you do not get it right, you can easily mix in the wrong measurements and damage the engine of your chainsaw. 

Having said that, if you end up making a mistake, it would be better to have a bit too much oil rather than having not enough oil. If you’re in doubt, you should prefer to be generous when adding oil to the gas. 

But what happens if you end up forgetting to add oil to the fuel that you’re putting in the chainsaw? You’ll be able to spot it pretty quickly. The engine will instantly start smoking within less than a minute and if you do not shut it off immediately, it’ll likely suffer irreparable damage.

How to mix gas and oil for a chainsaw?

When using a chainsaw with a 2-stroke engine, you can easily mix the gas-and-oil blend to use as fuel. There is no special technique or skill required. All that you’ll require is a gas can and something that will allow you to measure the volumes.

Start off by using a clean gas can

Not many people realize this, but the biggest cause of contaminated fuel is dirty fuel containers. It is important that you should store fresh gas in a clean, authentic container that is designed for carrying fuel.

Carefully measure and pour the oil and gas

It is important that you should measure the exact quantities of oil and gas in the mixture. Normally, most 2-stroke engines use a mixture having one part oil to 50 parts gas, giving it a 1:50 ratio. However, a few chainsaws also use a 1:40 oil-to-gas mixture.

Close the cap and finish up

Once you’ve added the oil and gas, you should close the cap on the gas. Give the thing a good shake and ensure that the two components are properly mixed.

Choose the right fuel and two-stroke oil for your chainsaw engine

Many chainsaw brands today sell high-quality two-stroke oil. This is the case as two-stroke engines tend to require two-stroke oil that is designed and formulated for high performance. It is recommended that you should go for a quality lubricant or two-stroke oil that you’ll mix with the gas. In case you’re not using a pre-mixed gas and oil blend, you should look to use unleaded ethanol-free gas.

Here are some tips that will help you choose the best two-stroke oil for your chainsaws –

  1. Never use two-stroke oil that is intended for water-cooled engines in a non water-cooled engine. This type of oil is usually referred to as outboard oil (rated TCW). Moreover, never use motor oil that is intended for 4-stroke engines like motor vehicle oil.
  2. Mineral oils normally cost less than synthetics, and they’re great for engine lubrication. These oils are made using a natural petroleum base and perform a good enough job cleaning and filtering engine contaminant. They can sometimes leave behind heavier deposits than their synthetic counterparts. Over time, you might end up with gummy residue or burnt carbon buildup on the piston. This can easily lead to more maintenance issues and compromised performance. Sometimes, manufacturers will mix additives that help in improving combustibility.
  3. Full synthetic oil will provide superior combustion characteristics while also delivering great lubrication. It will leave little to no mess that petroleum-based oils tend to leave behind. This will give you a much cleaner engine. They are normally formed using a mineral base, with additives like detergents, octane enhancers, and stabilizers. It helps burn cleaner in comparison to other engine oils while producing less smoke.
  4. Semi-synthetic oils will meet you down the middle. These oils generally comprise high-quality mineral oil. However, they are mixed with additives and synthetic polymers and deliver a cleaner burn as compared to strictly petroleum-based oils. Semi-synthetics will cost significantly less than full synthetic oils and offer great combustion properties. Further, they’ll give you better lubrication than what you would get from standard mineral oil.
mixing gas and oil in chainsaw

Top tips to remember when mixing chainsaw gas

  • It is smarter to use a separate gas can to store two-stroke fuel and oil mix. This way, you will not confuse it with the regular fuel intended for 4-stroke engines.
  • Avoid storing two-stroke fuel for more than a month.
  • If you want to prolong the lifespan of your mixed two-stroke fuel, you can use fuel stabilizers. They are available in the market and will help extend the shelf life of the fuel up to 12 months.
  • Make sure that you clean your gas cap and the surrounding area before you fill the gas. This will prevent any debris and dirt from falling into your gas tank.
  • Never leave any premixed two-stroke fuel for an extended period of time. Make sure to drain the tank and run your chainsaw out of fuel before you put it away.
  • Never mix oil and gas in the tank of your chainsaw. Instead, use an FM or UL-approved container.
  • Using the correct ratio of gas and 2-stroke oil for the chainsaw is important. If you mix the wrong amount or mix it improperly, the chainsaw will not run effectively. Further, it can easily get damaged.
  • Never attempt to refuel a chainsaw when it is still running. Always turn off your chainsaw and wait for it to cool down before you refuel.
  • Never try to start the chainsaw if there is fuel on your gloves, clothing, chainsaw area, or anywhere around you.
  • Under no circumstances smoke or use vape when adding gas or mixing the oil-gas mixture or using a chainsaw.
  • Never mix more than a month’s supply of chainsaw gas. Stale gas will break down over time, forming gummy varnish deposits that tend to clog the carburetor during chainsaw operation. The best thing to do is to buy and mix enough gas and oil to complete the next task.
  • Never store your chainsaw with any leftover fluid in the chainsaw’s fuel tank. Either use the chainsaw until the tank is empty or dump the mixture into an approved container for storage.
Correct Way To Mix Gas and Oil For a ChainSaw, WeedEater etc.


There you have it, hopefully, now you know how to mix chainsaw gas and oil and run your chainsaw smoothly. It is important to always get the ratio right when you’re mixing gas with the two-stroke fuel oil. If you add too much oil, the engine will struggle to start and generate carbon buildup. On the contrary, if you add little oil, your engine might overheat and sustain internal damage. The correct mixing ratio for most chainsaws is 1:50 with one part oil to 50 parts gas. Additionally, some chainsaw engines also use a mixing ratio of 1:40.

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Hi, I'm Mike - but my friends call me Backyard Mike. I'm the founder of this website, and I'm addicted to outdoor power tools. I love to work with wood and share my knowledge here on this website with you. You can find more about me here.