Gas engine

A spark ignition gas engine provided with a spark plug, the gas engine comprising a fuel inlet connecting piece connected to a mounting hardware piece provided in a cylinder head for housing the spark plug, thereby supplying fuel gas from the fuel inlet connecting piece to a pre-combustion chamber through a fuel passage provided in the mounting hardware piece, the fuel gas supplied in the pre-combustion chamber being ignited by spark discharge at the spark plug that is fitted on a fitting seat surface in the mounting hardware piece;

• wherein the gas engine further comprises:
• a solenoid valve that performs open-close control of the fuel gas which streams into a fuel inlet passage bored in the fuel inlet connecting piece;
• and
• a first check valve that is provided posterior to a discharge side of the solenoid valve in the fuel inlet passage, so that the combustion gas generated in the pre-combustion chamber is prevented from flowing backwards in a direction from the pre-combustion chamber toward the solenoid valve.