Linear momentum conservation, rooted in the spatial invariance of physical laws and formalized by Noether's theorem, requires that systems with spatial translational symmetry conserve linear momentum. This work examines how this principle applies to a charged retarded field engine, where the rate of change of total mechanical linear momentum and field linear momentum is balanced. Using electric and magnetic field expressions from a Taylor expansion to incorporate retardation effects, we analyze the linear momentum equation order by order for two arbitrary charged bodies. Our results show that total linear momentum is conserved, with mechanical and field linear momentum changes exactly balanced. Consequently, the linear momentum lost by the internal electromagnetic field precisely equals the engine's gained mechanical linear momentum, addressing the central focus of this study.