Thank you for clarifying.
If the ski still runs good on the top end, no noticeable decrease in top speed or acceleration, it sounds like you have picked up some debris in a low speed jet. That means the carbs are going to have to be removed and cleaned.
However, on your ski, that is one huge pain to do. The carbs are underneath the exhaust pipe and catalytic converter. It takes an experienced tech about 3 hrs or so to get the carbs off, cleaned and put back on. It can easily take triple that for someone who has never worked on this particular model before.
While going through the carbs and heading for the slow speed jets, obviously you want to scrutinize each component inside the carb just in case there are other items that need attention that could be contributing to the problem now or could create problems in the future. I would pay close attention to the fuel pump side of the carbs as well. It has a large mylar diaphragm that has been known to get perforated from a rough casting in the fuel check valve block and also inspect the check valves themselves to make sure they are not creased.
This would be a really good time to invest in a service manual if you are going to undertake this endeavor. You are going to need extensive details in dis-assembly order and reassembly order plus torque specs and other settings.
If there are any new developments or you come up with any more questions, feel free to add to this thread and I will get back to you.