The invention is directed to a mixture lubricated four-stroke engine having a cylinder and a piston which delimits a combustion chamber in the cylinder. The piston drives a crankshaft via a connecting rod with the crankshaft being journalled in a crankcase. An inlet valve and an outlet valve are provided for the combustion chamber and have respective valve members which are actuated via a valve drive assembly driven by the crankshaft. The inlet valve is connected via an intake channel to a mixture-preparation device. The valve housing is, on the one hand, connected to the crankcase and, on the other hand, is flow connected via a connecting channel to the intake channel. The crankcase is connected to the mixture-preparation device exclusively via the valve housing, the connecting channel and the intake channel. In this way, an adequate lubrication and excellent acceleration performance is ensured with a constructively simple configuration and excellent exhaust-gas quality.