When Honda redesigned their 2 hp outboard in the late 90"s one of the "improvements" they made to the unit was to eliminate the water pump thus simplifying the design. The previous engine was actually air cooled too, the difference is that the older engine had water mixed with the exhaust as it exited the engine. This significantly quieted the exhaust note at full throttle. I loved that old style engine and we owned one of the last ones until it was stolen. I replaced our's with a Yamaha 2.5. That is my current favorite small engine. It is small, very quiet and not too heavy.
The new Hondas are off my list primarily because of their exhaust note! They are the loudest engines in the anchorage when you give them full throttle. I am not sure how the noise ratings are measured but if you ever think that you may want to use the little engine wide open (the way most people seem to use them) then before you buy one get the dealer to run it in a tank for you and ask him to "open it up". You'll see exactly what I am saying. The other thing people seem to struggle with on these little Honda outboards is the centrifugal clutch. The Yamaha (and the Suzuki I believe) have an actual gear shift for neutral and drive, the Honda has a centrifugal clutch that engages drive when you give it throttle. This takes some getting used to when maneuvering at the dock. I have met more than one person who really hates the Honda system....
Just my 2 cents,
Bruce