The motor was painted when new. Just use it. It won’t change its appearance any. The gas tank is steel so when you take the motor off, wipe it down with something like WD-40 to keep it from rusting. What remains will evaporate after a bit. Use corn head grease or 105 in the gear case. If you are going to be running it a lot, you’ll want to get an idea of how often you need to add some. A gear case in good condition won’t use hardly any grease at all but, most have some ware. When your done for the summer open up the gear case and get all the water out. Grease Video Link- https://youtu.be/dAu2-zYmgGc?si=js6x6yU2cEfh2u_p
A "Boathouse Repair" is one thats done without having tools or the skills to do it properly.