Changing either the language or units can only be done using B.U.D.S. This is something you would have to have done at the dealership...hopefully they would not charge you for it, but I am guessing they would!
Not sure if I was clear in my previous post. B.U.D.S stands for Bombardier Utility Diagnostic System and this is the system the is used to diagnose problems and program your seadoo. This software is not readily available which is why I am going to assume you would have to get it done at an authorized dealer.
