TOPIC: Shifter Problems

Hey folks we have been having some troubles with our 1967 Gulfstream. It has an original Mercruiser 160 that runs like a dream and the boat itself is in really good shape having been garaged all its 40+ years, but yesterday on the lake we had a strange development. The boat had been working well except that it seemed to be shifting kind of slow. You would push the throttle forward and there would be a delay before it dropped into gear. Then you would have to pull it back beyond the neutral position to get it out of gear. We figured it was just an adjustment due to old stretched cables that we could fix once we got home. Then we launched it on the big lake (before adjusting it)and had a good runaround, but as we approached the dock in the wind and a bit of wave action the old man needed to make a few quick shifts. After a little jockeying around the old man once again shifted into revers and gave her a little gas, and i'll be damned if she didn't surge forward. Well long story short, we got her trailered, but now she shift into the forward gear when you pull the lever back and into reverse when you push it forward. HELP

The controler is the old panel mount(just the handle shows on the outside of the panel)with the button in the center.