Honda 50 4 stroke power upgrade

[Nuaticocat]

I recently purchased a 18 foot cc catamaran with a honda 50 four stroke. The boat is rated for 75 hp. Does anyone know of perfomance parts for this motor? Seems like it is a fairly simple engine, overhead cam , etc. I am new to outboards, but have worked an mucho powerplants. Any push in the right direction would help.
thanks