An engine starter includes a motor housing having an inlet and an outlet for a motive fluid, a fluid-driven motor within the motor housing, the motor including a rotor and a stator, the stator directing a flow of fluid over the rotor, thereby inducing rotation of the rotor about an axis and exerting an axial force on the rotor and an output shaft operably coupled to the rotor such that rotation of the rotor drives rotation of the shaft about the axis. A front and a rear ball bearing assembly support the rotor. A front biasing member is pre-loaded to exert a first biasing load on the front ball bearing assembly and a rear biasing member is pre-loaded to exert a second biasing load on the rear ball bearing assembly in opposition of the axial force exerted on the rotor. The biasing members distribute the axial force between the two ball bearing assemblies.