Cables

Was going for a spin yesterday and called it off after 50 odd K's. I seemed to have to much freeplay with the throttle so I pulled up to adjust the cable and promtly busted the adjuster!!!! (note- do not use pliers to adjust cable). So I head home and call in to my mechanic , after he pulls the throttle apart he pulls on the return cable and out she comes, rusted and busted and has been for a long time.I'm now getting two new cables but I'm wondering is the return cable nessessary as the rex seemed to be fine without it.
Cheers Eric.
Cheers Eric.