on both of my transom tie downs is a single word in sharpie.....it reads "PLUG!"
What if you forget to undo the tie downs? It has never happened to me on a Sunday in front of 30 people. Shake it, push it, bounce up and down on it, still won't float off the trailer. That's when you turn to your 1st Mate and give them a stare down.
My brand new Silverado 4X4 clunks occasionally going into reverse and when I put in 4X4 pulling the boat out on the ramp. Service letter from GM said it was fine. 65,000 miles later still clunks once in a while and it is fine.
It took me 2 years to finally know all the little tricks to start from cold start on my outboard. It's a used boat, there will be little tricks you need to learn that the previous owner knew and didn't tell you after you made the deal. The first thing I would have done though before splashing her was to do a full tune up at least for peace of mind if anything. Give her a few cans of Seafoam, it will help clean the gum in the fuel system, many here say it's a waste of $$, I use it and haven't touched my carbs in 9 years. Now watch!!
Something is going to go wrong, the when, where, what and why is the mystery but it will happen. We can't call a CAA tow truck on the water here.