Unless you have gallons of water running into the bilge, that amount of play shouldn't cause any major problems. You could get some wear on your prop shaft if you run countless hours, but should be fine if you're just using the engine to get in and out of the slip.
Just for general knowledge, the official Columbia Owners website is Here: columbiasailingyachts : Columbia Sailing Yachts
You'll find all the answers to all the questions, and it's a very active group.
Most of the owners gave up on the alternative forums when they changed formats, or ownership a few years ago.