A rotating separator has a housing preventing separated liquid carryover. A plenum between the annular rotating separating filter element and the housing sidewall has one or more flow path separating guides minimizing the flow of separated liquid to the outlet. The flow path guides may include one or more fins and/or swirl flow dampers and/or a configured surface.

A four-stroke engine for a working machine with a rod is provided, where a tool is attached to one end of the rod in a longitudinal direction and the four-stroke engine is fixed to the other end of the rod in use. The four-stroke engine includes: an oil circulation pathway; and a gas-liquid separating chamber configured to separate oil from blowby gas. The gas-liquid separating chamber includes: an inflow part into which the blowby gas is introduced from the oil circulation pathway; oil discharge parts configured to flow the oil separated from the blowby gas back to the oil circulation pathway; and a blowby gas discharge part configured to discharge the blowby gas not containing oil mist from the gas-liquid separating chamber and supplies the blowby gas to an intake passageway to a combustion chamber.