1990 200hp johnson/Spray Tune up

[Chasing Tails]

This outboard is new to me this season. A friend that owns the same year 225hp Evenrude recommended that I spary a can of johnson/Erude tune up to loosen any carbon build up.
Questions: is this a good idea even if the motor is running fine. If so where do I spray it? in the carborators or spark plugs?
Is this can in addition to adding carbon gaurd in the fuel?

Thanks!!

[boats.net]

Yes is fine even if motor runs good. Spray through the carburetors.