[salty dog]

There are many on the forum more knowledgeable than I and could add their recommendations. I would say all the gas should be drained; treated or not, if it's been several years, it's way too old. If it's a carbed engine, you may want to have it cleaned, jets. etc. to remove residue. Points, plugs, cap/rotor are probably all needing replacement. In other words, a complete tuneup. I would certainly replace out-drive oil and impeller. An oil change for sure and most likely, I'm sure you'll need a new battery. I would also check other fluid levels; IE steering etc. As I said, others can chime in to add to the list. or correct me on any points. Good luck.