People sink these things all the time.
Obviously not the ideal thing to do, but it happens.
Drain all the water, add fresh gas, start it up and let it run for a while to dry out. I would do that a couple times over several days, then fog it real good for the summer.
Fogging it will get down into the case where just adding oil to the cylinders don't.
'92 Indy 650
'95 Indy XLT 600, plastic skis, skid plate, cobra windshield, XTRA 10, full Fox package, 1" riser