First, are you sure that you didn't accidently put it in the "limp" mode, which limites speed and rpms? It would be really weird for the engine to be running perfectly normally and you are not going anywhere unless you have sucked someting up the pump and damaged the impeller, etc.. Push the unlock button on the remote and you should hear 2 beeps. Three beeps = Low RPM mode and the "L-Mode" light on the dash will be on. Hold the unlock button for at least 4 seconds to switch between modes.
Second, check for error codes. If there is a sensor malfunction, etc., that will also limit RPMs. I think on your model you push and hold the "Select" button for 10 seconds to display the codes (01 is normal).
If the above are OK, then check the RPMs like Outlaw says on the water when you are at WOT. Should be around 10,000. That will help tell if it is an engine or pump problem. Then report back.