Not a Kawasaki man, but here are the basics, roll the jet ski in a manner to purge the exhaust pipe of water ( back pressure build up will keep it from starting ) Pull the air cleaner/ spark arrestor. Pull the spark plugs and push out as much water as possible, fogg it good down each spark plug hole with WD 40. Crank and crank! Dont use starting fluid! Choke it until you smell gas in spark plug holes. Re install plugs and try to start, pull plugs and dry and clean, repeat until success. DONT WAIT, do this ASAP, if you get it running, you need to run it easy and get it up to temp. After it getts running you might want to fogg the cylinders with injection oil and runn it some more.
Good luck