GAS ENGINE WITH BORE COOL HOLES HAVING SPARK PLUG

Provided is a check valve structure capable of preventing soot accumulation in a check valve arranged in a pre-combustion chamber (4) due to incomplete combustion of fuel gas and preventing malfunction the check valve (6) for a gas engine having an pre-combustion chamber with a spark plug. An arrangement for supplying fuel gas to the pre-combustion chamber (4) has a multiple bore-cooling holes (11s) disposed around the spark plug (10) for cooling a gasket (10f) formed in a mounting hardware piece (13), the holes having an lateral bore-cooling hole (11a), and a lateral bore-cooling hole (11b) with the gasket (10f) therebetween. Each of the holes further has a multiple bore-cooling holes (11s) parallel to the center axis (10a) of the spark plug. The mounting hardware piece (13) further has a check valve (6) communicating with a fuel gas inlet slot (5) between the lateral bore-cooling hole (11a)(inlet side) and the lateral bore-cooling hole (11b) (outlet side) for cooling water so that the check valve is cooled. A first check valve (22s) is provided upstream of a fuel gas inlet location (the junction) (14s) of the mounting hardware piece (13) with respect to the fuel flow to prevent reversed flow of fuel gas.