Stihl FS 490 C-M Instruction Manual - Page 30

English WARNING If the mounting nut has become too loose, fit a new one. NOTICE Remove the tool used to block the shaft. Removing the cutting attachment N Block the shaft. N Unscrew the mounting nut clockwise. N Pull the cutting attachment with its mounting hardware off the gearbox. Fuel This engine is certified to operate on unleaded gasoline and 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 a lower octane rating 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 even damage the engine. For this reason STIHL recommends that you use only high-quality unleaded gasoline! For further details, see www.STIHLusa.com/ethanol Use only STIHL two-stroke engine oil or equivalent high-quality two-stroke engine oils that are designed for use only in air cooled two-cycle engines. To ensure the maximum performance of your STIHL engine, use a high quality 2cycle engine oil. To help your engine run cleaner and reduce harmful carbon deposits, STIHL recommends using STIHL HP Ultra 2-cycle engine oil or ask your dealer for an equivalent fully synthetic 2-cycle engine oil. To meet the requirements of EPA and CARB we recommend to use STIHL HP Ultra oil. 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.). 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 any 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 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 28 FS 460 C-M, FS 460 C-M L, FS 490 C-M, FS 490 C-M L