engine seems froze on my 87 Larson

by george
(New York)

I recently purchased a 1987 Larson with a V-8. The previous owner swears the boat started normally.
It hadt been started for about 8 months prior to my purchasing it in "as is" condition. The previous owner is a friend of mine so I have no reason to doubt his sincerity. Besides he practically gave me the boat given what I paid for it.
The problem is the starter sounds like its kicking in but the engine doesnt crank. My frind says he had a problem some time ago with the starter. I tried turning over the engine manually by using a breaker bar on the bottom pulley. It wouldnt turn. I am told that it may not be possible to turn the engine over using this method. I really want to verify that the engine is not frozen due to lack of use or something more major. I put Marvel mystrey oil and some other chemicals down the spark plugs holes in case the cylinders were rusted but with no change.
Any suggestions?
Is there some sort of engine locking engagement I need to be aware of?
Maybe the transom locks the engine?