A starter motor for an internal combustion engine has an electric motor, a shaft driven by the motor, and a pinion assembly arranged to engage a flywheel of the engine. The pinion assembly has a drive collar mounted to a helical spline of the shaft, an output gear and an elastic member disposed between the drive collar and the output gear. A connection shell prevents axial separation between the drive collar and the output gear. The elastic member prevents direct contact between the connection shell and at least one and possibly both of the drive collar and the output gear.