A port injection system for gaseous fuels may include an injector body defining a hydraulic fluid inlet chamber, a hydraulic fluid exit passageway, a hydraulic fluid actuation passageway, a check valve inlet passageway fluidly connected with the hydraulic fluid actuation passageway, a valve chamber, and a gaseous fuel inlet chamber. An electrical solenoid actuator may be mounted to the injector body, with the electrical solenoid actuator including a movable armature, and a poppet valve connected to the movable armature and disposed within the valve chamber. The poppet valve may be movable between a pressurized hydraulic fluid flow blocking position and a pressurized hydraulic fluid flow passing position. A check valve may be disposed within the check valve inlet passageway. A gas admission valve may be disposed at least partially within the gaseous fuel inlet chamber and in contact with the check valve such that movement of the check valve by hydraulic fluid entering the check valve inlet passageway results in actuation of the gas admission valve away from a normally closed position closing off the gaseous fuel inlet chamber to a fuel injection position wherein gaseous fuel is allowed to flow from the gaseous fuel inlet chamber into an intake manifold or intake port of an engine on which the injector body is mounted.