Abstract: An internal combustion engine including a cylinder and a fuel delivery system for delivering a fuel and air mixture into the cylinder. The fuel delivery system has a rapid action check valve located between a fuel source and a conduit to a combustion chamber of the cylinder. The rapid action check valve has a valve body with a channel therethrough and a valve plate connected to a front end of the valve body. The valve plate has an outer section and a center cantilevered flap. The cantilevered flap extends inward from the outer section in a generally cantilevered fashion. The cantilevered flap is located at a front end of the valve body at the channel and is deflectably moveable in a forward direction away from the channel.