Stihl Oil Mix Ratio Chart for Chainsaws: All You Need to Know

Mixing fuel for Stihl chainsaws can feel like an uphill struggle. Since Stihl chainsaws feature a 2-cycle engine, they require the recommended mixture of gasoline and oil to run efficiently. Failure to use the correct mixture results in the engine’s low performance and reduced chainsaw’s lifetime.

If you can access the operator’s manual, check the manufacturer’s recommended fuel-to-oil ratio. What if you don’t have the manual or don’t want to go through it looking for the figures?

Thankfully, this article provides a Stihl oil mix ratio chart you can use when adding fuel and oil to your chainsaw. You’ll also learn why you should use the correct oil mix ratio.

Oil Mix Ratio for Stihl Chainsaw

Stihl gasoline-powered chainsaws use a 50:1 fuel-to-oil mix ratio. That means the mixture should have 50 parts of gasoline and 1 part of lubricating oil. This mixture should be ideal for lubricating engine parts and protecting them from excessive friction and heat.

This fuel-to-oil mix ratio applies to all Stihl chainsaws with a two-cycle engine. The 50:1 is easier to calculate than in some chainsaws that require a 40:1 mixing ratio.

The 50:1 gasoline/oil mixture indicates that you require 2.6oz of oil per gallon of gasoline. Let’s see how we’ve arrived at 2.6 ounces of oil.

One gallon of gasoline = 128 ounces (oz.), so when using the 50:1 mixing ratio, you’ll need 2.6 ounces of oil per 1 gallon of gasoline. 

If you’re mixing gasoline in liters, use the same 50:1 ratio. In this case, you’ll need 20 milliliters of oil per 1 liter of gasoline. So, why use 20 milliliters of oil?

  • 1 liter of gasoline = 1000 milliliters. So if you’re using the 50:1 ratio, you’ll need 20 milliliters of oil per 1 liter of gasoline. 

If doing all the calculations when creating the mixture appears daunting, you can rely on the table below to make your work easier.

Stihl Oil Mix Ratio Chart

Use this table when mixing fuel in gallons.

Fuel Quantity (Gallons)Oil Quantity (Ounces)

When mixing gasoline in liters, use the table below.

Fuel Quantity (Liters)Oil Quantity(Milliliters)
120 ml
240 ml
360 ml
480 ml
5100 ml
6120 ml
7140 ml
8160 ml

How To Mix Fuel With Oil for Stihl Chainsaws

After knowing the right mixing ratio, you’ll need to blend the two products correctly. First, ensure you have the recommended fuel and oil for your chainsaw.

When choosing gasoline for the chainsaw, it’s advisable to go premium. Stihl recommends mid-grade unleaded gasoline, whose octane rating is 89.

Gasoline with a lower than 89 octane rating can increase the engine temperature. Eventually, the heat might damage the piston and various engine parts.

Regarding oil, choose 2-stroke oils for your Stihl chainsaw. If you don’t want to scour the market looking for the appropriate oil, use the Stihl HP Ultra Oil.

This oil is a fully synthetic 2-stroke and has outstanding cleaning characteristics. It’s highly biodegradable and will protect your chainsaw engine against friction and heat.

When mixing fuel with oil, look for a no-spill fuel can to reduce evaporation, permeation, or spillage.

The steps below should help you create the mixture appropriately:

  • Start by pouring the oil into the can. You must ensure that your no-spill can is clean.
  • Pour fuel into the can.
  • Close the no-spill can and shake it vigorously. Shaking the container will allow fuel and oil to mix and be ready for use.

Clean the fuel cap before adding this fuel/oil mixture to your chainsaw. You can wipe the cap with a clean cloth to remove any dirt that might contaminate the mixture. When removing the cap, apply caution to avoid inhaling fuel vapor.

Create a sufficient fuel-to-oil mixture that will last a few days. The goal is to mix enough fuel that will remain fresh while minimizing the chances of buildup.

Why Use the Right Oil Mix Ratio for Stihl Chainsaw?

A proper fuel-to-oil mix boosts your chainsaw’s engine performance. It lubricates moving parts and reduces heat that might damage the engine. Parts that are more susceptible to damage include the piston, cylinder, and crankcase.

Always follow our Stihl oil mix ratio chart when mixing gasoline with oil. Using gasoline only in your chainsaw can have some detrimental impacts. The Stihl chainsaw has a 2-cycle engine that can generate much heat if it uses gasoline only.

When gasoline combusts alone, the engine parts create a lot of friction and heat. The rings, rubbers, and bushes might melt if the engine overheats. If you continue using the chainsaw, it can succumb to severe damage that might require the replacement of the entire engine.

What Happens if You Add Too Much Oil to the Mixture?

Like gasoline, your chainsaw will act up if you add too much oil to the mixture. If your mixture has too much oil, the chainsaw will produce excessive smoke upon starting the engine. 

The oil and smoke may leak out of the muffler. If you use the chainsaw to cut logs, the engine will overheat and lose power.

Excessive oil can deposit carbon and clog up the system. As a result, air fails to move in and out, causing the engine to overheat. You might also notice a burning smell of oil and strange noises from the engine.

To fix this problem:

  • Drain the fuel from your chainsaw. You can start by removing carbon buildup from the engine with a wire brush or putty knife.
  • Use a solvent to clear the remaining carbon deposits.
  • If there are stubborn spots, remove the metal parts and soak them in a solvent for about 15 minutes.

After removing the carbon buildup, add a proper gasoline-to-oil mixture into the chainsaw tank. Run the engine to see if you’ve resolved the problem.

Is There Any Premixed Fuel for Stihl Chainsaws?

Does mixing gasoline with oil feel daunting? Thankfully, you can go for the ready-to-use Stihl MotoMix premixed fuel. MotoMix is a high-performance fuel that works with almost all Stihl engines. It’s convenient since you don’t need to work out the calculations, mix and shake the solution.

Furthermore, the MotoMix fuel offers excellent lubrication while minimizing emissions. Remember that you should use this fuel with Stihl engines and not engines from other brands.

Bottom Line

Using the correct fuel-to-oil mix ratio can keep your Stihl chainsaw running smoothly and increase lifespan. Generally, Stihl engines use a 50:1 gasoline/oil mix ratio. If you want to add the correct mixture to your chainsaw, follow our Stihl oil mix ratio chart.

Use the recommended fuel and oil to keep the engine in good shape. The best gasoline to use is mid-grade unleaded gas, whose octane rating is 89. Regarding oil, go for synthetic options like the Stihl HP Ultra Oil. Alternatively, you can use the ready-to-use Stihl MotoMix premix fuel.