Hi and thank you for your question.
This is certainly not a known problem or common.
I have my suspicions about what is going on but would like more information about your ski.
First, does it have any non factory modifications done to it, perhaps something like performance upgrades?
Does it make any difference if you were to run it for say 30 minutes, grab your drink and come back, would it do it then?
Exactly what is it doing? Does it try to stall and you have to feather the throttle to keep it going?
Will it not take full throttle and you have to mostly idle until it gets going?
Does it sound like it is loading up?
What brand of oil are you using, and are you running the stock oil injection?
Has the ski had any work or service of any kind done on it lately?
Did it just start doing it?
If you could fill me in on those answers, plus add any additional information if you think of it, it will help me pin point the problem.