Stihl FB 131 Instruction Manual - Page 9

- In hot environments, cooling will take longer. - The engine is air cooled. When it is shut off, cooling air is no longer drawn across the cylinder and the engine temperature will rise for several minutes before starting to cool. After the power tool has cooled appropriately, follow the safety instructions in this chapter for removing the cap. Never remove the fuel filler cap by turning it directly to the open position. First check for residual pressure in the tank by slowly turning the cap approximately 1/2 turn counterclockwise. The cap should be held in place by the threads while allowing residual vapor/pressure to be relieved. Once the fumes or vapor have been relieved, turn the cap further until it can be removed from the tank opening. Use only good quality fuel that is appropriate for the season (summer v. winter blends). Some blends of gasoline, particularly winter blends, are more volatile and can contribute to fuel spraying. Removing the Threaded Fuel Filler Cap WARNING After allowing the power tool to cool, remove the fuel filler cap slowly and carefully to allow any remaining pressure build-up in the tank to release: - While maintaining steady, downward pressure, slowly turn the cap approximately 1/2 turn counterclockwise. - If any significant venting occurs, immediately re-seal the tank by turning the cap clockwise to the closed position. Allow the power tool to cool further before attempting to open the tank. - Turn the cap to the open position only after the contents of the tank are no longer under pressure. - Never remove the cap by turning it directly to the open position. First allow the power tool to cool adequately and then release any residual pressure by slowly turning it approximately 1/2 turn counterclockwise. - Never attempt to remove the cap while the engine is still hot or running. English Installing the Threaded Fuel Filler Cap WARNING Unit vibrations can cause an improperly tightened fuel filler cap to loosen or come off and spill quantities of fuel. To reduce the risk of fuel spillage and fire, tighten the fuel filler cap by hand with as much force as possible. Damaged or Broken Cap If your fuel cap does not tighten properly, it may be damaged or broken. Stop using the power tool and take it to your authorized STIHL dealer for repair. Vapor Lock WARNING Vapor lock occurs when fuel in the fuel line or carburetor vaporizes, causing bubbles to block the free flow of liquid fuel into the carburetor. Vapor lock cannot be relieved or affected by opening the fuel tank. Removing the fuel filler cap without first allowing the power tool to cool adequately can result in fuel spraying. Always follow the instructions in this section when removing the fuel cap. FB 131 7