You should gain some top end as well as better performance when loaded.
As far as Sinkers claim of Yammies being that much better than Mercs I don't believe it.
Sorry Sinker
We had Mercs and Yammies and they were equal in performance and reliability.
I would not recommend Honda's though as we tried a batch out at one of the lodges and the lower units were much less robust than the Yammies and Mercs. The lower units would blow apart itf you hit rocks while the others would hold up well under most impacts.
1000's of pics on here and I can't find one with me without shades and a hat on. I don't want to post a 15 year old pic 40 pounds heavier than now. I'll ask my wife if she has any.
Then it wouldn't be fair my Buckeye pal.I don't think I'll see it in my lifetime.
Gino, my wife pointed out that the guy in photo's 5 and 6 could be my twin. She might be right. I don't think I have a recent, 25 years, pic of me without my hat and shades on and I'm not holding a fish. I'll look.
https://www.thehulltruth.com/boating-forum/446047-what-considered-lot-hours-outboards.html
A lot of variables, a 25hp motor may not have been on a boat with a bow or transom electric motor and was the only source of power?
400 hours is not high for 4 stokes.
We used 30 hp 4 stoke Mercs up at the lodge I worked at and they probably had 2000 hours or more when they were replaced.
I believe once you get over 1200 hours they are starting to get up there.
I'm not understanding the apprehension of hitting Lake Erie with an 18 footer with a 140 on the back , a 14 foot tinner with a 9.9 yes, but your boat is very capable of a lot of days on Erie.