My 2 horse 4 stroke Honda was sunk in sea water for a period. What are the chances that someone can make it operable again? Thanks for the advice.

Is it still in the water? If not, how long has it been out of the water?

Usually if you take it out of the water you should take the plug(s) out then pull the rope or starter to get as much water out as possible then, change the oil and gear oil in the lower unit. now spray some engine fogger or quicksilver powertune into the carb(s) and into the plug hole to get inside the cylinder.
choke it and keep cranking until you get it started.
If it ran before it sank and it hasn't corroded internally it should run after you do this. Run it good then change the plug(s) and sparay the motor down with a corrosion guard type spray.

If by chance it has been out of the water for a while and has begun to corrode, go to an auto parts like advance or napa etc. and get a bottle of Rislone (an oil additive). add some to your oil and try turning it over then also pour a little of this in your plug hole(s).
try turning it over then let it sit a while then try again and this will help free the valves and cylinder(s).
this will also help to clean it internally so after you get it running and let it run a while change the oil again.