I've narrowed down my starting problem on my Mercury 7.5 1982. I believe it is either the battery or the starter. What is happening is that the starter clicks on and the Bendix spins but does not raise high enough to engage the flywheel. The battery was my neighbor's that he bought new a few years ago but never used. I charged it up and put it on the boat. Started the motor a few times with no issues until the last time I tried it. The gear on the starter does not look worn at all. Starter or Battery?