no it is too old .. you have to take it apart - it will not turn because oil and water are inside the cylinder , take the plug out and it will move then clean carb if you are looking for short cut. lower unit does not have water in it since it is seal .. things are about to rust all over if you dont use that engine soon..
Take out spark plugand drain, fill with anything that's hydroscopic like fresh diesel or the liquid wd-40, roll engine around, pull crank, and try to get in all areas of engine. Empty. Drain bowl on Carb and flush with wd -40, and make sure to run some through jets.
Replace spark and start ASAP before rust takes it too far.
If already completely frozen, you'll have to rebuild completely. You can try some of the "deep penetrating" lubes sprayed into the cylinder through the plug hole, but I've had very limited luck. And, if there's rust on the piston or cylinder, it'll score as soon as it starts, which is pretty unavoidable and will require a rebuild.
On the brightside, my Grandpa's 83 merc 7.5 was sunk at least 4 times, and came back each time, before it finally fell off my boat in 80 feet of water.