I am new to PWC, and just bought 2 97 GTX units. Recently while riding I noticed one of them was slower than the other, and that the impeller area was not as quiet as the other. When my son had it out last week it was much slower, and impeller areas was making a whining sound. He immediately shut it down, and quit riding it. When I went to start it, it doesnt turn over. Could this be an rebuild to the impeller, or motor issues now? Please let me know any thoughts.