Navy, I know evinrude/Johnson motor well as I have both a 1986 225 and a 1991 225. I am going to run the 86 first as it has slightly smaller pistons (3.5in vs 3.65 in I think) so I'm assuming that fuel consumption may be slightly less. Just a guess.
You are correct that these motors are thirsty by today's standards but super easy and cheap to fix/maintain. That's exactly why I am going with these motors as I can fix them in my sleep now. If I happen to find a spare $15,000 laying around, I would love to upgrade to an etec, but until then I will keep these workhorses going. A good trick is to run the evinrude xd 100 full synthetic oil as it barely smokes and smells sweet as opposed to choking to death in the white toxic puff cloud of cheaper oil.
On a side note , the only difference between the 200 and the 225 are the carbs and the throttle plates the carbs are bolted to. You can get them almost anywhere for cheap. I don't want to whisper bad things in your ear as you are already over powered for the hull but it is at least a possibility.
The same applies with 150's and the 175's.... Carbs. But the bigger difference from the 150 to the 175 is the 150 has a 10 amp charging system while the 175 jumps to 35 amps. However you can get 175 flywheel, stator, power pack, rectifier and timing ring for cheap and upgrade your 150 to a 35 amp system. I have a set available as i was going to convert a 150 for my 200ccp before I got the 246ccp which is too big for a 150. We will replace it in the spring either way.
Lastly, thank you for yours and your families sacrifice and service to this great country. If there is anything I can do to help you let me know.