Stihl recommends using a mix of 50 parts gasoline and 1 part oil in its two-stroke weed trimmer engines. This means a 2.6 ounce bottle of oil should be mixed into 1 gallon of gas. Always use unleaded gasoline with an octane rating of 89 or higher to avoid damaging the engine and never use oil that is rated as BIA or TCW -- two-stroke water.. Each of these engine types requires a gas and oil fuel mix. 4-MIX engines combine the pros of a 4-stroke engine while using a gas and oil mix to keep its compact form. Unlike other 4-stroke engines on the market today, STIHL does not require a straight gas. STIHL 4-MIX string trimmer models: FS 91, FS 91 R; FS 111, FS 111 R, FS 111 RX; FS 131.
Summary: How to mix gas for weed eater. Using the right fuel mixture in your grass trimmer protects it from damage such as piston seizure We recommend using STIHL 1:50 2-stroke engine oil with gas , at a mix ratio of 1:50 - 1 part oil to 50 parts of petrol If you're using a different brand of oil, make sure it has the TC classification.. To mix oil and gas for a STIHL weed eater, you just need to go through an easy process that is gently shaking. Then why is mixing oil and gas so important for STIHL weed eaters? Because all that matters is the ratio of oil and gas and the type of oil and gas you are using. The STIHL weed eaters use two-stroke engines that complete one.