Sleepy- A lot of the problems with the XP's if you read in the forum is fuel related issues. From my own headaches with XP's I would try these things first:
1. If your fuel lines are the original grey tempo lines, change them. You can use 1/4 inch automotive fuel line from AutoZone or Advanced Auto, whatever you have in your area; that is the cheap, but effective way. If you really want to get fancy you can buy marine rated fuel lines, but to be honest I don't think it's worth the extra money.
2. Check your internal carb filter. This is one of the most common problems I have seen in this forum. If you don't know exactly how to check those there are indepth instructions on carb rebuilds on this website as well as YouTube.
3. While you have the carbs off check your seals and gaskets. It never hurts to make sure!
4. Check you fuel selector value. These things tend to get clogged with the old grey fuel lines.
5. Finally, check your voltage regulator. You can check this two ways: By hooking up a voltage meter to the battery and starting the ski. You should read 13-14 volts on idle and 15.5 on WOT on the hose. The second way is to disconnect the red wire coming out of the regulator,(there are 4 wires, one that is red and three that are yellow) Put the ski in the water and you should see an immediate difference. Remember doing it this way does NOT charge your battery, so only do this for a short period of time.
Do those few things see if that helps!