An engine system including: an engine configured to output shaft power by burning fuel, and a system main portion configured to operate using the shaft power of the engine. The engine system further includes: an operation controlling unit, and a power source unit configured to convert commercial power to operating power and supply the operating power to the operation controlling unit. The power source unit includes: a system main portion-side power source unit configured to supply operating power for controlling the operation of the system main portion, and an engine-side power source unit configured to supply operating power for controlling the operation of the engine. The system main portion-side power source unit and the engine-side power source unit are provided individually and separately from each other.

An engine system including: an engine configured to output shaft power by burning fuel, and a system main portion configured to operate using the shaft power of the engine. The engine system further includes: an operation controlling unit, and a power source unit configured to convert commercial power to operating power and supply the operating power to the operation controlling unit. The power source unit includes: a system main portion-side power source unit configured to supply operating power for controlling the operation of the system main portion, and an engine-side power source unit configured to supply operating power for controlling the operation of the engine. The system main portion-side power source unit and the engine-side power source unit are provided individually and separately from each other.

An engine-driven working machine includes a controller, which varies a control value of a solenoid valve so as to decrease or increase an opening degree of the solenoid valve when a rotating speed of an engine is within a predetermined high rotating speed range and the rotating speed of the engine is lower or higher than a predetermined rotating speed, respectively. When the control value of the solenoid valve is varied so as to decrease the opening degree of the solenoid valve and corresponds to a predetermined opening degree larger than a fully-closed state, the control value is set to a limitation value.

An engine-driven working machine includes a controller, which varies a control value of a solenoid valve so as to decrease or increase an opening degree of the solenoid valve when a rotating speed of an engine is within a predetermined high rotating speed range and the rotating speed of the engine is lower or higher than a predetermined rotating speed, respectively. In case the controller determines that the engine-driven working machine gets started saw cutting, the controller stops varying the control value of the solenoid valve when the rotating speed of the engine is within the predetermined high rotating speed range and lower than the target rotating speed.