In an automotive carburetor, the time delay in the response of the engine to the change in the cross sectional area of the air passage is minimized, and a high level of freedom in selecting the communication cross section area of the air passage and the air fuel ratio for the given load of the engine. The carburetor (1) comprises a fuel passage (13) including a fuel nozzle (16) for supplying fuel to the intake passage, a first air passage (14) communicating with the fuel passage to supply air to the fuel passage, a variable communication unit (21, 41) provided in a part of the first air passage and moveable between an open position for communicating the first air passage and a closed position for shutting off the first air passage and a switch mechanism (22, 43) for moving the variable communication unit between the open position and the closed position in dependence on a load of the engine.

A mixture formation apparatus, especially for an internal combustion engine of a working device, has a mixture formation apparatus housing, where a surface of the mixture formation apparatus housing is provided at least partly with a layer structure for protection from corrosion and/or deposits. The layer structure has at least one aluminium oxide layer having a layer thickness of at least 10 m. A method of manufacturing the mixture formation apparatus, and a working device or an internal combustion engine having the mixture formation apparatus, are disclosed.

A mixture formation apparatus, especially for an internal combustion engine of a working device, has a mixture formation apparatus housing, where a surface of the mixture formation apparatus housing is provided at least partly with a layer structure for protection from corrosion and/or deposits. The layer structure has at least one aluminium oxide layer having a layer thickness of at least 10 m. A method of manufacturing the mixture formation apparatus, and a working device or an internal combustion engine having the mixture formation apparatus, are disclosed.

A fuel bowl system for a carburetor has a fuel bowl with a cavity configured to receive and store liquid fuel prior to delivery to the carburetor. The fuel bowl has a main structure extending from an outer surface of the fuel bowl. The main structure has an inlet for receiving liquid fuel from a fuel source and discharge passages in fluid communication with the inlet and the cavity. A cap is removably connected to the main structure. The main structure and the cap together define fuel delivery channels in fluid communication with the inlet and the discharge passages. The inlet directs liquid fuel received from the fuel source into the fuel delivery channels, the fuel delivery channels deliver the liquid fuel into the discharge passages, and the discharge passages discharge the liquid fuel into the cavity of the fuel bowl.

A fuel bowl system for a carburetor has a fuel bowl with a cavity configured to receive and store liquid fuel prior to delivery to the carburetor. The fuel bowl has a main structure extending from an outer surface of the fuel bowl. The main structure has an inlet for receiving liquid fuel from a fuel source and discharge passages in fluid communication with the inlet and the cavity. A cap is removably connected to the main structure. The main structure and the cap together define fuel delivery channels in fluid communication with the inlet and the discharge passages. The inlet directs liquid fuel received from the fuel source into the fuel delivery channels, the fuel delivery channels deliver the liquid fuel into the discharge passages, and the discharge passages discharge the liquid fuel into the cavity of the fuel bowl.