Chainsaw Gas Mix | Easy Step-by-Step Instructions

If you’re a first time chainsaw user it can be easy to overlook this one simple thing when it comes to your chainsaw gas mix.

Unlike a car that has a separate engine oil compartment/dipstick along with a gas tank for fuel storage, on chainsaws these are both combined in the fuel tank.

Forgetting this step could ruin your expensive chainsaw. We’ll make it super simple for you to figure out how to easily get the right gas oil mixture.

Why Are Gas And Oil Mixed For Chainsaws?

Unlike a car engine, a two-stroke engine needs a mixture of fuel and oil to ensure proper engine combustion and lubrication.

Pouring Gas To Oil Mixture Into The Chainsaw Fuel

In two-cycle engines, the air-fuel mix comes in direct contact with the pistons and other parts that need lubricating. An air-fuel mix that has oil in it will lubricate these parts while the engine is running.

What Happens If You Forget To Mix Oil In With The Gas?

Oil is important for any engine and chainsaws are no different. Using the wrong ratio of gas and oil can cause catastrophic engine failure.

If you forget to use a mixture of gas and oil, you may encounter a piston seizure and experience total engine failure.

Best Gas To Use In Your Chainsaw

The best fuel to mix with oil for chainsaws is ethanol free gas. This is sometimes called “boat gas” from a place like Wawa.

While not necessary, a chainsaw will run on a regular gas mix, ethanol free gas will last longer and keep your machine’s internal parts in better working order.

That being said, unleaded gasoline with an octane rating of 89 is the lowest rated fuel you’d want to use. This is the minimum octane rating recommended by reputable chainsaw manufacturers like STIHL.

Gas with a lower octane rating may not burn properly in your chainsaw and cause performance issues or even damage.

Pre-Mixed Gas

If you’d rather not deal with ratios and mixing gasoline with oil, you can buy a premixed fuel online or from a local store. Check your chainsaw’s manual before buying anything to figure out if you need a 50:1 or a 40:1 premixed fuel.

Using The Proper Gas-To-Oil Ratio

Not all engines use the same ratio of mix. Be sure that you mix chainsaw gas according to the manufacturer’s recommended ratio to avoid damaging your engine.

The first number in the ratio is gasoline and the second number is two-stroke oil. So a 50:1 ratio is 50 gasoline fluid ounces and 1 ounce of oil, but most mixes are calculated by the gallon.

50:1 Mixture

50:1 mixtures require 2.6 fluid ounces of oil for every one gallon of gas. 2.5 gallons of gas need 6.4 ounces of oil and 5 gallons of gas will need 12.8 ounces of oil.

40:1 Mixture

40:1 mixtures require 3.2 fluid ounces of oil for every one gallon of gas. 2.5 gallons of gas need 8 ounces of oil while 5 gallons of gas will need 16 ounces of oil.

Step By Step For Proper Gas Oil Mixture

If you want to mix chainsaw gas at home, it’s very simple to do as long as you keep a few things in mind.

Gasoline vapors are extremely flammable and can ignite easily so make sure there are no open flames nearby. Inhaling fuel vapor is also dangerous, so be sure to make your mix in a well-ventilated area.

Step 1: Gather Everything You Will Need

It helps to have everything you need on hand before you actually start mixing the gas. Here’s a quick list of everything you need to make a mix.

  • Ethanol Free Gas Preferably
  • Two Stroke Oil
  • An Approved Container for Gasoline or Gas Mix

Step 2: Find Out What Ratio Your Chainsaw Needs

Before you mix fuel, you need to know what ratio to make. Check your chainsaw’s manual or the manufacturer’s website to find out the correct ratio.

Step 3: Calculate How Much Oil You Need

Now that you know the correct ratio, multiply the number of gallons you have in your approved container by either 2.6 for 50:1 mixes or 3.2 for 40:1 mixes. This number will be the total ounces of oil you add to the gasoline.

Most bottles of two-stroke oil mixture will tell you how many gallons each full container makes. Read your bottle carefully if you’re unsure or check how many ounces it is.

Step 4: Mix The Gasoline And Oil

Now that you have your ounces of oil counted out you’re ready to add it to the gasoline.

Once you’ve added the oil, close the container and ensure the oil is evenly distributed throughout with a light shake. After that, you’re all set to add your mix to the fuel tank.

If it’s a regular gas can, it’s best to mark on the jug that it is a 50/50 mix so you don’t forget.

What Not To Do

You cannot mix regular motor oil with gasoline instead of two-stroke oil. It may work at first, but over time it can cause damage to your chainsaw’s engine.

Do not use unapproved containers. Only use approved containers when mixing gasoline.

Make sure you mix sufficient fuel with the proper amount of oil. Too little oil or an imbalance in the mix can cause your engine to not run efficiently.

Final Thoughts

Making your own chainsaw mix at home is easy and after doing it just once you’ll feel comfortable doing it again in the future. Follow the simple steps we’ve laid out here and you won’t have any problems with your chainsaw.

Frequently Asked Questions (FAQ):

Can I Use 50:1 Gas in My Chainsaw's Fuel Tank?

It depends. Check your chainsaw's manual to see if your saw needs a 50:1 or a 40:1 mix.

What Is the Best Mix Ratio for Chainsaw Gas?

The best mix ratio for chainsaw gas is the manufacturer-recommended ratio. Some chainsaws use a 50:1 mix while others use a 40:1. Check the manual or manufacturer's website to decide which mix ratio is right for you.

How Do You Know if Your 2-Stroke Fuel Has Too Much Oil?

It's hard to tell just by looking at your mix. If your chainsaw has a difficult time starting or is blowing an unusual amount of smoke out of the exhaust, it's best to stop what you are doing and replace the fuel inside of it. Too much oil can damage the engine, so it's best to just try again with a new, proper mix.