1984 Johnson 90 leaking?

Looking at a cheap small lake boat that has a 1984 Johnson 90 horse on it. The current owner says its leaking water between the lower unit and the main unit. I'm not to familiar with the old johnson motors and was wondering what could cause this problem? I was thinking it is maybe a bad seal? Thanks

If you are talking about the seam between the lower and the mid section that is normal. There is no gasket between them.