No fishing, but out testing a new sonar yesterday.
Water had 18"-20" visibility on a gold 1/2 oz blade bait.
According to the DNR Officer I asked, you are not allowed to fire/start/run etc... any motor over 10hp on the lake. Including to load/unload.
That was a few years ago, so unless something has changed, I would guess that's still the case.
I have a 90 Hp Mercury Optimax. But I also have a 1980 6 hp Evinrude that I use for lakes with HP limits. It doesn't scream across the water but it's almost twice as fast as using my electric trolling motor. And it doesn't create much wake pushing a 16.5 foot Alumacraft Navigator 165CS. I bolted a seperate transom board so it wouldn't scratch the paint while taking it off and putting on.