I threw my Quicksilver (Merc) model 3000 in the trash for the same reason. Now I have a 2000 butttttt it mounts on the outside with the cables visible and you may not want that on your Proline. I wanted the exposed fast idle that the 2000 gives you. I wouldn't rebuild one as on mine the insides were ALL worn out anyway. Just get another I guess.
Mark
Here's a couple pix of my control.