Abstract: In an internal combustion engine (2) of a portable handheld work apparatus, the cylinder (3) is provided with cooling ribs (4, 4?). A cooling airflow is generated by the fan wheel (13) and is guided over the cooling ribs. A carburetor (9) is temperaturized as required by the heated cooling air. A control of the cooling airflow to the carburetor (9) takes place in that an opening (11), which passes the heated cooling air, is selectively closed or opened via a closure element (12). In order to obtain improved cooling of the cylinder during summer operation as well as during winter operation, the closure element (12) is provided with at least one air guide wall which extends essentially transversely to the cooling airflow and causes this cooling air to be partially backed up and deflected.

Abstract: A carburetor for an internal combustion engine has a carburetor housing and a mixture forming passage provided in the carburetor housing. A throttle and a choke valve are rotatably arranged in the mixture forming passage on a throttle shaft and a choke shaft, respectively. A lever arrangement has a throttle adjusting lever mounted on the throttle shaft and a choke adjusting lever mounted on the choke shaft. The throttle valve and the choke valve are adjustable in several operating positions and the lever arrangement assumes appropriate positions corresponding to the operational positions, respectively. A release device for releasing a locking action between the throttle adjusting lever and the choke adjusting lever when an emergency stop is actuated is provided. A spring forcing the choke adjusting lever in a direction toward an engagement plane with the throttle adjusting lever.

Abstract: In an internal combustion engine (2) of a portable handheld work apparatus, the cylinder (3) is provided with cooling ribs (4, 4?). A cooling airflow is generated by the fan wheel (13) and is guided over the cooling ribs. A carburetor (9) is temperaturized as required by the heated cooling air. A control of the cooling airflow to the carburetor (9) takes place in that an opening (11), which passes the heated cooling air, is selectively closed or opened via a closure element (12). In order to obtain improved cooling of the cylinder during summer operation as well as during winter operation, the closure element (12) is provided with at least one air guide wall which extends essentially transversely to the cooling airflow and causes this cooling air to be partially backed up and deflected.

Abstract: A carburetor for an internal combustion engine has a carburetor housing and a mixture forming passage provided in the carburetor housing. A throttle and a choke valve are rotatably arranged in the mixture forming passage on a throttle shaft and a choke shaft, respectively. A lever arrangement has a throttle adjusting lever mounted on the throttle shaft and a choke adjusting lever mounted on the choke shaft. The throttle valve and the choke valve are adjustable in several operating positions and the lever arrangement assumes appropriate positions corresponding to the operational positions, respectively. A release device for releasing a locking action between the throttle adjusting lever and the choke adjusting lever when an emergency stop is actuated is provided. A spring forcing the choke adjusting lever in a direction toward an engagement plane with the throttle adjusting lever.

Abstract: In an internal combustion engine (2) of a portable handheld work apparatus, the cylinder (3) is provided with cooling ribs (4, 4?). A cooling airflow is generated by the fan wheel (13) and is guided over the cooling ribs. A carburetor (9) is temperaturized as required by the heated cooling air. A control of the cooling airflow to the carburetor (9) takes place in that an opening (11), which passes the heated cooling air, is selectively closed or opened via a closure element (12). In order to obtain improved cooling of the cylinder during summer operation as well as during winter operation, the closure element (12) is provided with at least one air guide wall which extends essentially transversely to the cooling airflow and causes this cooling air to be partially backed up and deflected.