TOPIC: starting an old 2 stroke merc 25

Hey my grandpa has a 25 horse 2 stroke mercury 1998 outboard that has just been sitting in his garage for a few years (2?) since he got rid of his whaler. I recently acquired what i believe is a 14ft crownline hull that I want to throw it on.

Can anyone direct me to any good threads or give me advice regarding what precautions I need to take before starting up engines that have sat for a few years?

Thanks