Flooded boat help

Absolutely do not try to crank it. A mechanic will have to make sure there is no water trapped anywhere. Depending on how well the boat was wired it may be ok, it's made to withstand a marine environment after all, but I wouldn't turn anything on unless you want to be chasing shorts around for months. The other concern is the hull, I know the industry has moved away from foam but if its in there it will be full of water. There's just too much that COULD be wrong to even begin to tell you how to start, your best bet is letting insurance handle it and if they say its yours to salvage then pull it to someone who knows what they're doing.

Drop the oil, take the plugs out, take the oil filter off and plug with a rag, fill the cylinder and the oil pan with diesel, let it sit. Take all the electrical connections apart, clean then and coat with dielectric grease. Remove the carb if it's not injected, clean the shite out of it. The battery is prob shot, get a new one. Drain the diesel out the oil pan, turn the engine over to blow the diesel out the cylinder. Refill with oil and marvel mystery oil, replace the plugs. Replace the carb, make sure you clean the gas tank and refill with good gas and prime the carb. Give it a shot of starting fluid and cross your fingers. If it starts, let it run for a minute, and change the oil and filter, add some marvel mystery oil and you should be good. Done this on a new outboard last year.