Stihl FB 131 Instruction Manual - Page 19

Fuel This engine is certified to operate on unleaded gasoline and the STIHL twostroke engine oil at a mix ratio of 50:1. Your engine requires a mixture of highquality gasoline and two-stroke air cooled engine oil. Use mid-grade unleaded gasoline with a minimum octane rating of 89 ((R+M)/2) and no more than 10% ethanol content. Fuel with an octane rating below 89 may increase engine temperatures. This, in turn, increases the risk of piston seizure and damage to the engine. The chemical composition of the fuel is also important. Some fuel additives not only detrimentally affect elastomers (carburetor diaphragms, oil seals, fuel lines, etc.), but magnesium castings and catalytic converters as well. This could cause running problems or damage the engine. For this reason STIHL recommends that you use only quality unleaded gasoline! Gasoline with an ethanol content of more than 10% can cause running problems and major damage in engines and should not be used. For further details, see www.STIHLusa.com/ethanol The ethanol content in gasoline affects engine speed - it may be necessary to readjust the carburetor if you use fuels with various ethanol contents. WARNING To reduce the risk of personal injury from loss of control and / or contact with the running cutting tool, do not use your unit with incorrect idle adjustment. At correct idle speed, the cutting tool should not move. If your power tool´s idle speed is incorrectly adjusted, have your authorized STIHL servicing dealer check your machine and make the proper adjustments and repairs. The idle speed and maximum speed of the engine change if you switch from a fuel with a certain ethanol content to another fuel with a much higher or lower ethanol content. This problem can be avoided by always using fuel with the same ethanol content. To ensure the maximum performance of your STIHL engine, use a high quality 2cycle engine oil, such as STIHL 2-cycle engine oils. STIHL 2-cycle engine oils are specially designed for STIHL engines. To help your engine run cleaner and reduce harmful carbon deposits, STIHL recommends using STIHL HP Ultra 2-cycle engine oil, or use an equivalent high quality 2-cycle engine oil. To meet the requirements of EPA and CARB we recommend to use STIHL HP Ultra oil or equivalent. Do not use NMMA or TCW rated (twostroke water cooled) mix oils or other mix oils that state they are for use in both water cooled and air cooled engines (e.g., outboard motors, snowmobiles, chain saws, mopeds, etc.). English Take care when handling gasoline. Avoid direct contact with the skin and avoid inhaling fuel vapor. When filling at the pump, first remove the container from your vehicle and place the container on the ground before filling. To reduce the risk of sparks from static discharge and resulting fire and/or explosion, do not fill fuel containers that are sitting in or on a vehicle or trailer. The container should be kept tightly closed in order to limit the amount of moisture that gets into the mixture. The machine's fuel tank should be cleaned as necessary. STIHL MotoMix STIHL recommends the use of STIHL MotoMix. STIHL MotoMix has a high octane rating and ensures that you always use the right gasoline/oil mix ratio. STIHL MotoMix uses STIHL HP Ultra two-stroke engine oil suited for high performance engines. For further details, see www.STIHLusa.com/ethanol Fuel mix ages If not using STIHL MotoMix, only mix sufficient fuel for a few days of work, not to exceed 30 days of storage. Store in approved fuel-containers only. When mixing, pour oil into the container first, and then add gasoline. Close the container and shake it vigorously by hand to ensure proper mix of oil and gasoline. FB 131 17