Abstract: A number of embodiments of gaseous fueled internal combustion engines having induction systems that include charging augmentation means for altering the charging character of the induction system into the combustion chamber. In some embodiments this charging augmentation means comprises auxiliary intake passages that serve the combustion chamber through the main intake passages and which deliver a charge at a higher velocity. This higher velocity charge may be employed to generate tumble in the combustion chamber. The charge forming system for the engine includes a number of embodiments of systems including a carburetor and a pressure regulator that delivers fuel at a regulated pressure to the carburetor. In some embodiments, fuel is also delivered to the induction system independently of the carburetor.