Start the engine and let it run until the engine is warm and running smoothly. After the engine is warm, turn it off and wait five minutes. Disconnect the fuel line from the carburetor and injectors. Attach a small container below the carburetor or injector line and loosen the bleed screw with a screwdriver. Air bubbles will come out from the fuel line. Tighten the bleed screw and reconnect the fuel line to the carburetor or injector. Restart the engine and check that the fuel is flowing properly.