help gts acting funny

hey i just bought a 97 sea doo gts. the only problem until now is the starter solenoid was bad (i changed that). but now i am having a few more problems. when i first put it in the lake today for the third time this season. i started it and it seemed to idle pretty ruff. it also made this high pitched squeeking sound (sounded like from the pump). i figured it was a little bit of a bug that just needed to be worked out (first of the season problems). so i drove it a little bit and the sound went away and it seemed fine. so me and two of my friends went out on it and it could not get up to speed. the engine was reving up but it took a while to get ahead of our own wake. i figured that was normal for almost totally waiting it down with 3 people (three seater) but it seemed to get a little worse as time went on so i took them back. when i was on it by myself i would give it gas (not to fast) and i would hit the rev limiter for a second almost as though it was cavitating (this did not happen the first two times i was on it, which the second time i had one passenger and it was fine). then it would finally grab the water after a few seconds and get moving.it sat over ngith and i went out today when this started happening.i did not do anything to the ski overnight. it was yesturday i drove it and it worked fine the only difference is i got some shell medium grade gas. sorry this is long i am trying to make it as detailed as possible. thanks for your help.