So what happens in very sub zero areas ? Most of their winter.
Please NO O B lovers reply's.
I personally drain the water, pull the TS, fill with AF and all is good.
Did that with Glycol. The first Summer when I saw green water on the first splash, I thought that ain't good. In future years I ran it on the muffs in Spring and let it run in the grass. In later years I used -50 pink stuff so I didn't contaminate the waterways.
Regardless of method my last step was to draw a pint out of the block into a glass jar and put it on the tongue of the trailer. My boats are garage kept so I could look at the jar every day as I jumped in the car to go to work.
My experience with an I/O was 35 years. I now have 2 OB boats in the garage. I won't admit to being a lover. My switch had nothing to do with Winterizing. It was simply because of U-joints, bellows, extra weight and the new need for a cat converter.
Never had an issue. The caveat is that it was not MOST of the Winter. Maybe a week or 2 below zero and the garage was at single digits or low teens.
I have friends that stored their boats outside and merely drained the water. One DID have a cracked block. I don't know if his procedure included pocking the holes, but obviously he still ahs some water that didn't drain.