Water in Engine
I assume your engine is flooded with water.
The engine has no drain plug.  Pull the spark plugs, place an old rag over the spark plug holes and turn the engine over a few times.  This will get rid of most or the water.  Spray some fogging oil down the spark plug holes, and turn it over a few more times.
Pour a little premix down the spark plug holes, any premix is o.k., like weed eater, chain saw.  Replace the spark plugs, start the ski and let it run for a few minutes.  If the ski is out of the water connect it to a garden hose, after you have started the ski.
Lou