The acoustomechanic efficiency of a turbulent jet is determined as the ratio of acoustic radiation power to the kinetic energy flux of the jet. According to the Lighthill acoustic analogy, the acoustomechanic efficiency of axially symmetric jets is proportional to the fifth power of the Mach number. In this paper, on the basis of an experimental study and an analysis of published data, the influence of various factors that can affect the structure of a jet and, consequently, its acoustomechanic efficiency is investigated. In particular, the influence of water injection on the reduction of the jet noise is analyzed. The results of analyzing experimental data show that a systematic deviation from the relation between acoustic and mechanical jet energies obtained from the Lighthill acoustic analogy arises in the case of the outflow of low-velocity jets of low density and with the development of longitudinal vorticity in the flow.