Combustion engine and hand-held work device with a combustion engine

The engine has crankcase (4), a crankshaft and a cylinder that is rotated around rotational axis. The crankcase has circumferential wall that is arranged extending in circumferential direction, and is provided with fuel retaining unit (10). The fuel retaining unit has an extension in the radial direction and in the circumferential direction. The fuel retaining unit has asymmetrical cross-section relative to the radial direction in a circumferential direction. An independent claim is included for hand-guided tool.