it is on a 1982 Sea Ray, how do l take the shift lever off, its a side mount.l need to take it off to get to the control box?

In my experience it is most likely the control cables causing ur problems. The lubrication inside them dries up & makes shifting difficult. They r not very expensive in the scheme off things so replace them. You Will notice a big difference.

As for control removal, they r bolted or screwed thru the side of the interior. You may have to access the back side by cutting out an acces hole very close buy & then install an access plate over the hole once u r finished.