To do this they would have had to cut and bend the centre wire of the throttle cable, cutting off the ball, and mimicking the screw in hook of the G3 cable, however I doubt it would retain full function, as the reason the original cable as a coil thread and a hook screwed in, is the need for rigidity in that hook.
The bent end of a centre wire would struggle to apply enough pressure to the G3 carby's cut out pin in order to stop the engine.