$1000 is way too high for a ski that you know without a doubt is going to need a new motor, or at least many new parts (if its been sitting that long the crank is gone as well as everything else in there). Its only worth the value of the hull plus a little more for the electrics (and there is no guarantee that the electrics work, and don't be surprised if the pump is rusted together), etc.. I'd offer $500-600
Man you are going to have your own used ski business before long if you keep collecting.