Sounds like the carb needs to be rebuilt and new fuel filter.
Did you ever figure this out? Mines doing the sameSo I took out the jet skis yesterday for the first time of the season. I got it started up. I put new gas in and new oil. I was riding for about an hour or so no problems, and suddenly when I would go full throttle my ski would just shut down completely. I would start it back up and when I get it back up to full throttle, after about five seconds it would shut off again. I am not very inclined on jet skis and would like some feedback. Thank you.