I would think if you are running a carbon preventer product like seafoam in your gas all the time you should be ok. I have owned 4 outboards and not a single one of them I have ever decarbed, however I have always run a carbon cleaner/stabilizer in my gas. Once a year I will run a shock treatment tank of gas through the motor and all year run the reccomended regular use dose in it. This seems to keep everything clean and the motor running strong. Before I started running seafoam the inside of my prop was full of that carbon buildup. Just a few tanks of fuel with seafoam in it shined it right up. That can only lead me to believe its cleaning the internals. My yamaha Im running right now is an 07 and seafoam has been run in it since day one, and the inside of my prop is as clean as a whistle. I have heard alot of good things about Evinrudes XD100 oil that it actually cleans carbon buildup, and you do not need to do the 1 time a year decarb when you run this oil. If you can suffer the price its about 35 a gallon bulk, might be somthing to look into. I recently switched to Penn. Full syn. and saw a huge difference in performance, its an ashless formula thats suppose to help limit carbon build up. It without a doubt burns cleaner in my motor, my plugs look new with quite a bit of time on them and the smoke at start up is gone.
scott
