An internal combustion engine has a cylinder with a combustion chamber and a piston supported reciprocatingly in the cylinder and delimiting the combustion chamber. A crankcase is connected to the cylinder and a crankshaft is rotatably supported therein. The piston is operatively connected to the crankshaft so as to drive the crankshaft in rotation. A transfer passage provides flow communication between crankcase interior and combustion chamber when the piston is at bottom dead center. The transfer passage has a port opening connecting the transfer passage to the crankcase interior and has a transfer port connecting the transfer passage to the combustion chamber. A fuel supply device supplies fuel into the transfer passage at a location between the transfer port and the port opening. The transfer passage has a connecting opening and is connected to the crankcase interior at the connecting opening. A control element controls the connecting opening.

An internal combustion engine has a cylinder with a combustion chamber and a piston supported reciprocatingly in the cylinder and delimiting the combustion chamber. A crankcase is connected to the cylinder and a crankshaft is rotatably supported therein. The piston is operatively connected to the crankshaft so as to drive the crankshaft in rotation. A transfer passage provides flow communication between crankcase interior and combustion chamber when the piston is at bottom dead center. The transfer passage has a port opening connecting the transfer passage to the crankcase interior and has a transfer port connecting the transfer passage to the combustion chamber. A fuel supply device supplies fuel into the transfer passage at a location between the transfer port and the port opening. The transfer passage has a connecting opening and is connected to the crankcase interior at the connecting opening. A control element controls the connecting opening.

An internal combustion engine has a cylinder with a combustion chamber and a piston supported reciprocatingly in the cylinder and delimiting the combustion chamber. A crankcase is connected to the cylinder and a crankshaft is rotatably supported therein. The piston is operatively connected to the crankshaft so as to drive the crankshaft in rotation. A transfer passage provides flow communication between crankcase interior and combustion chamber when the piston is at bottom dead center. The transfer passage has a port opening connecting the transfer passage to the crankcase interior and has a transfer port connecting the transfer passage to the combustion chamber. A fuel supply device supplies fuel into the transfer passage at a location between the transfer port and the port opening. The transfer passage has a connecting opening and is connected to the crankcase interior at the connecting opening. A control element controls the connecting opening.

An internal combustion engine has a cylinder with a combustion chamber and a piston supported reciprocatingly in the cylinder and delimiting the combustion chamber. A crankcase is connected to the cylinder and a crankshaft is rotatably supported therein. The piston is operatively connected to the crankshaft so as to drive the crankshaft in rotation. A transfer passage provides flow communication between crankcase interior and combustion chamber when the piston is at bottom dead center. The transfer passage has a port opening connecting the transfer passage to the crankcase interior and has a transfer port connecting the transfer passage to the combustion chamber. A fuel supply device supplies fuel into the transfer passage at a location between the transfer port and the port opening. The transfer passage has a connecting opening and is connected to the crankcase interior at the connecting opening. A control element controls the connecting opening.

A carburetor for a hand-guided power tool has a carburetor housing and a carburetor rotor supported rotatably in the carburetor housing about an axis of rotation. A needle is disposed on the carburetor rotor and projects into a fuel opening of the carburetor. An adjusting element is operatively connected to the needle so as adjust a position of the needle relative to the carburetor rotor. The adjusting element has an engagement contour that is to be engaged by a tool for adjusting the adjusting element. A securing contour that is fixedly connected to the carburetor rotor is provided. The securing contour, at any point of the securing contour, has a spacing to the axis of rotation of at least approximately 10 mm.

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.