Mercruiser 470 Flooded

Man I made a terrible mistake. I forgot to pull the drain plug when I stored my boat, the cover collapsed and the boat got flooded in a rain storm.

The engine was about 50% submerged. I drained everything. New gas, new oil, new oil filter, turned it over a couple times with the plugs out to blow out any water that may have been in the cylinders, but none.

Now the oil is milkshake no matter what I do, the boat fires up and wants to run, but I haven't run it more than thirty seconds at most.

I have drained the oil three times, replaced the oil and filter each time and I'm still getting milkshake colored oil.

I'm at a loss, I don't want to keep pouring more oil into the boat hoping it's going to come back clean. I know there has to be someone out there with a solution? I'm just hoping I didn't destroy the engine for a stupid mistake.

If water entered the crankcase no amount of flushing with oil will get it clean. Pour about 2 gallons of diesel fuel in the crankcase and just spin the motor .
Drain and refill with 3 qts of oil and 1 qt diesel fuel and run the motor for 5 minutes, drain oil, refill and change oil filter.
Now to get rid of the moisture, you will have to run the motor under load for about an hour or so at normal operating temp.
The remaining moisture will boil out from the oil.

Bt Doctur said:

If water entered the crankcase no amount of flushing with oil will get it clean. Pour about 2 gallons of diesel fuel in the crankcase and just spin the motor .
Drain and refill with 3 qts of oil and 1 qt diesel fuel and run the motor for 5 minutes, drain oil, refill and change oil filter.
Now to get rid of the moisture, you will have to run the motor under load for about an hour or so at normal operating temp.
The remaining moisture will boil out from the oil.

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Thank you SO much!!

I was terrified I had ruined it, I'm hoping a compression test will tell me I still have some life in that engine.