MY 1996 SEaDoo GTI feels like the impeller is slipping. It starts and runs fine but it will noy get out of the hole. Does the impeller have a rubber hub like a boat prop does? Can the drive shaft spin inside the the impeller?
Some how the fastening device that fastens your impeller has either come loose or is missing. Take you impeller off and check that. If that is not the problem, and your drive shaft is still spinning inside of the impeller, then I don't know what else it could be?