Ranger is scheduled to deliver my 2020 Z518L at the end of April. The boat will be powered by a 2020 Mercury 200HP Pro XS. What are your experiences running ethanol-free fuel (hard to find) versus fuel with ethanol in these newer 4-stroke engines? Have these engines been designed to handle fuel with ethanol? Any fuel system issues?

Nothing wrong with running 10% ethanol

87 octane w/ 10% ethanol is what the motor is designed for.

They told me just to add some Staybil.. in my mercury pro xs 150..

I run gas with ethanol in my Merc 4 stroke.
Add a stabilizer if you don't fish often.

I have run ethanol gas since 1989. I always add ring free and Marine stabil to the gas. I have never ever experienced an ethanol related problem. That has been in two engines that I bought new. One was a 1989 Evinrude that I had on 89 Ranger. The only issue I had with the Evinrude was the VRO pump and it drank fuel/oil like there was no tomorrow. Great engine though. I traded that boat/engine in for a 2012 Ranger with a yamaha F150 four stroke. So far with that motor I change the engine oil once a year and the blue water filter every other year. In the last two years I have now been able to get non ethanol gas at a Buckees. But I don't because of the big difference in price and never have had ethanol issues.

Will ruin your fuel lines. Be ready to change out annually
I run e free in my XS 95% of the time, any other time I’ve used regular gas, I’ve mixed the additives with it (Dons Cocktail)

Not true at all. Pretty much every boat made in the last decade or so come with fuel lines rated for use with ethanol.

Lol, you're joking i hope

I think that’s all in how you read the manual. I don’t read mine in those terms. I read it as the best gas possible should be used but if you have to use ethanol it will not harm the motor. As such I use ethanol free whenever possible.

Not true on new motors but old ones it would eat fuel lines but E10 gas has been around so long those lines would have already been affected unless unless the engines been mothballed for 15+ years. E10 gas is fine if you run it out often but even letting it sit more than 2 weeks can start to cause problems with water absorption in the fuel. I pay the premium for the ethanol free gas.

My 1972 85hp Johnson had no problems with ethanol. I ran it from 1992 - 2009. Several times it sat for six months, once due to back surgery and again after shoulder surgery. No fuel additives.

I should have clarified...my neighbor has had to replace rule lines several times but he’s always used the regular fuel and his boat isn’t that old.
I’ve never had any issues with mine but I don’t hardly ever run e10

That thing probably has rubber fuel lines and the plastic that ethanol eats wasn't even invented back then

Two free apps I have on my phone at all times. Pure Gas shows ethanol free gas all over the US and Canada. Not always completely accurate but dang close: https://www.pure-gas.org/ The other is Gas Buddy. Shows diesel and gas prices in just about all towns. It will show prices closest to you or you can type in any town and it will show the prices. On road trips this is nice because diesel can vary by as much as $.50 a gallon(or more) from town to town. https://www.gasbuddy.com/