A weft feeder for gripper or projectile looms allows an operator promptly to restore the continuity of a weft yarn from a yarn feed spool to members for weft insertion into a loom shed, in case of weft yarn breakage or interruption. Downstream of a first yarn guide outlet, there are mounted a double-leaf brake, a separating element, and a second downstream yarn guide eyelet. The separating element is controlled by an actuator so as to separate two brake leaves of the double-leaf brake and to form a duct to guide the weft yarn from the first eyelet to the second eyelet.