Ahh… Repower time
You’ve already gotten some good advice. Find. Local. Motor. Support. First. Second decide how much you wanna spend. How many people and weight that will be your cruising weight. What is your gas storage scenario. I run with 4 Tempo 5.5/6 Gal portables. Determine what an acceptable cruising speed is for you. ‘Cause while WOT may clean out the carbon in cylinders, it is rarely dun -unless I want to carry 2 or 3 tanks for refill. Cruising speed for me is ~2700 at ~10mph, 15 tops, for anywhere I’m going. Those tanks run out faster as u increase cylinders
While I may not go that far, ~ 3-5 mis / outing; I expect to carry home and refill a tank a week. And more time than not I bob on my mooring
With all this being said, I’ve had the PO’s 35HP, a V3 ‘06 90 Hp Etec and currently run a V4 115 Etec Pontoon. The 35 was carbureted and I swapped out first year, 17 years ago. It had dirty carbs and burned me once. I RE powered to a V3 Etec 90 in ‘06. In hindsight, This was my Most Efficient motor. I ran a 13 spline prop but can’t remember their diameters. I’m guessing 12 or 13” diam, low pitch. I carry A lot of “Shtuff”, have a 260W Solar array and a high Bimini. Even when I was sailing, I had raised my gooseneck about 10”s. Look in my post history. For me, it was Well worth it for cabin comfort. I use a 4 bow 8’x8’ Bimini that’s connected outside of cockpit, along the top of my rubrail.
I cruise, hangout on my boat 98% of my 17 year ownership. I don’t/ haven’t sailed often. This year,and probably following, I’m going “Commando” and have left the sail hardware at the house. I’m not filling my ballast, in fact, I capped it with a 4” cover and ride high and dry.
Back on topic, I bought my V4 115 Etec in 2015. While there is no going back and I like spinning a 15.5 x 13 prop, this is the top of what I’d hang off a Mac transom. I don’t like having an external oil tank, but I only I fill it once a season, so far. Lastly, 4 strokes are Really Quiet! But require more maintenance… But are more enjoyable on the water, while driving. I can’t hear my radio or talk when I’m moving with my 2 stroke. But I like being able to Winterize in my driveway, at end of season. So far, so good. PS. Learn how to change out your lower unit oil
TLDR:
Decide your budget and local support. Go as big as you dare. I only get 25MPH with my setup; Which affects higher speeds but I’m not looking to run this boat higher than it’s specs. I’d also look into a 5-12” Jack Plate with wedges, depending on steering variance to open up your rear access area. After warranty goes I’d put on some type of wide “dole fin” to help with trim. Pick a practical RPM/speed.
Hope I didn’t just ramble but that this was informative. YMMV.
My .02
