Welcome aboard Snookin.
90's and 115's are usually the same power head, just carb differences - you can check the weights and you'll see they're identical. Are you going to go with new or rebuilt? There is a place down here in Bradenton, Ellis Outboards, that does a fine job of rebuilding and selling rebuilt motors that look and operate like new, for less than half the cost of new. I put one of his rebuilt Johnson 115s on my 170 and it runs perfect and now has about 60 hrs on it after about 2 years. You can google motors on the internet and get great deals on new ones too.
I think with motor tilted up, you'll be floating in about a foot of water and you'll be able to run in 2ft of water with no problems - of course is running that shallow good for the seabeds you're running through?
Again, welcome aboard and welcome to the 170/175 family.
