this is what I do. I first suck out some gas from the tank in a clear container to make sure it is clean and no water.
I hook a 1 gal gas can directly to the engine with half jar of Mercury Quick clean. Run for 10 minutes let set for 10 then run for 10 more. Hook back up to internal tank and run again. Then I change my plugs. I don't think anyone mentioned grease. New grease in any fittings you can find. I also check my bilge pump. Put plug in run hose to see if it is working. Should come on by itself. This is a carbed outboard.