FS 40, FS 40 C, FS 50, FS 50 C English 19 This engine is certified to operate on unleaded gasoline and the STIHL two- stroke engine oil at a mix ratio of 50:1. Your engine requires a mixture of high- quality 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. NOTICE Fuel with an octane rating below 89 may increase engine temperatures. download Wireless Network Lab Manual there. This, in turn, increases the risk of piston seizure and damage to the engine. New Holland 268 Operators Manual download. 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!

View the instruction manual for all of your STIHL power equipment sold within the U.S. FS 120, FS 200, FS 250; FS 130; FS 131, FS 131 R; FS 160, FS 180; FS 240.

NOTICE 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 an incorrect idle adjustment. At correct idle speed, the cutting tool should not move. If your machine’s idle speed is incorrectly adjusted, have your authorized STIHL servicing dealer check your machine and make the proper adjustments and repairs.