Stihl chainsaws are the best-selling chainsaws in the United States for good reason. They not only are reliable, but they also provide superior performance.
Their line of chainsaws is used by both homeowners and professionals. Using the right type of fuel in your Stihl chainsaw will help you protect the fuel system and engine for many years of use.
Stihl chainsaws with 2-cycle engines use a gas and oil mix at a ratio of 50:1. Stihl chainsaws require unleaded gasoline with a minimum octane rating of 89 and a maximum ethanol content of 10%. This gas is mixed with a 2-cycle premium oil that is ISO-L-EGD and JASO M345 FD certified.
Mix gas and oil in a well-ventilated area. Wear safety glasses to protect your eyes.
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Follow all safety instructions provided in your equipment operator’s manual before diagnosing, repairing, or operating. Consult a professional if you don’t have the skills, or knowledge or are not in the condition to perform the repair safely.
Gas and Oil to Use in a 2-Cycle Stihl Chainsaw
Know the type of engine you have on your chainsaw. Stihl currently manufactures chainsaws with 2-cycle engines. If you are using a different brand of chainsaw, you must make sure you know the kind of engine being used.
Most gas-powered chainsaws on the market today use 2-cycle engines, however, you will find 4-cycle chainsaws which require a straight gas. Don’t make the mistake of adding straight gas to a Stihl 2-cycle chainsaw or you will end up ruining it and most likely have to buy a new one.
Straight gas runs very dry and will cause a 2-cycle engine to seize up and quit. Without oil added to the gas, the engine doesn’t get the lubrication it requires for internal parts to move freely.
Stihl Chainsaws Use a Gas to Oil Fuel Mixture of 50:1
The 2-cycle engine on your Stihl chainsaw has one fill port for gas and oil mixed at a ratio of 50:1. This means it requires 50 parts gasoline to 1 part oil. For example, one gallon of gas requires 2.6 ounces of oil. Refer to this chart for the right amount of oil to mix with unleaded gas.
| Gas to Oil Mix | 1 Gallon Gas | 2 Gallon Gas | 2.5 Gallon Gas |
|---|---|---|---|
| 50:1 | 2.6 oz Oil | 5.2 oz Oil | 6.4 oz Oil |
Type of Gas to Use in a Stihl Chainsaw
When selecting gas for your Stihl chainsaw, always use fresh gas. When gas gets old, it begins to break down and become less combustible.
Gas with ethanol attracts moisture from the air to the fuel leaving behind a varnish in the fuel system. Gummy deposits will clog fuel components and prevent the carburetor from working sufficiently.
This can result in problems with your Stihl chainsaw not starting, dying, or experiencing a loss of power.
Stihl chainsaws require unleaded gasoline with a minimum 89 octane rating and a maximum 10% ethanol content. You can find this gas at your standard fuel station. Mix this gas with a 2-cycle premium oil.
Never use gasoline that has a greater ethanol content of 10% like those sold as E15, E30, and E85. These types of fuel contain up to 15%, 30%, and 85% of ethanol respectively. A low ethanol content or an ethanol-free fuel is best.
Type of Oil to Use
Stihl chainsaws require a premium 2-cycle oil that is ISO-L-EGD and JASO M345 FD certified. You can find Stihl branded 2-cycle oil sold as Stihl High Performance or Stihl HP Ultra for your chainsaw. Note: 2-cycle oil is not the same as automotive engine oil. Do not use standard engine oil in your chainsaw.
Pre-Mixed 2-Cycle Fuel
Stihl offers a pre-mixed fuel that contains an ethanol-free fuel and oil. This is a convenient option to have sitting on the shelf. There is no need to deal with the mess of mixing oil and gas in a gas can. The best thing about pre-mixed fuel is that you won’t have to deal with fuel problems caused by ethanol.
| Manufacture | Gas to Oil Mix | 2-Cycle Oil | Premixed Fuel |
|---|---|---|---|
| Stihl | 50:1 | High Performance HP Ultra | 2-Cycle MotoMix |
How to Mix Gas and Oil
Determine how much fuel mix you want to prepare. Refer to the chart above for the amount of 2-cycle oil to add to the gas.
- Remove the cap from an approved gas can. Add unleaded fuel (minimum 89 octane rating & maximum 10% ethanol content) to a gas can.
- Add the appropriate amount of 2-cycle oil to the gas can.
- Replace the cap.
- Gently shake the fuel and oil until they are mixed.
- Add to the chainsaw’s fuel tank.
Always mark your gas can with the type of gas or gas/oil mix in the can. Mistakenly adding the wrong fuel to a piece of equipment can damage it. You may be able to remember you mixed fuel in a certain fuel can, but someone else may not know.