Hi-I have made a stupid mistake! Had ski out on trailer and was checking a weak battery, had ski run for about 10 seconds and decided to hook up the water supply to on the inlet to the sand filter. All going great and ran the engine for about 1 minute or so on water all looking good. Shut off ski and was hooking up a voltmeter to see if the battery was getting a charge. Note: water was still on and going at full pressure........ Seems I managed to fill the exhaust muffler and the expansion chamber and water backed up into the cylinders (mainly the rear cylinder). I turned off the water and tilted the ski up to drain as much as I easily could. Then blew compressed air into both cylinders and sprayed fogging oil in both cylinders...... What else should I do? Also looked at the repair manual and the parts manual and could not see a lower crankcase drain plug.........did see the magneto expansion bladder by the starter, but I don't think that will help in this case.

Appreciate any QUICK assistance and guidance

Thanks in advance,