First season with my 2000 31 Da had the marina that pulled the boat winterize the motors .I went ahead and did the water works in the boat with the pink stuff.So I used the back flush method basically I hooked up a drill pump pushed it into thru hull fitting with some tade wraped around the hose to help seal it on the side of the boat pulled the anti freeze out of the bottle elevated above the fitting to help things along turned on the drill on and a minute or so later out it came from the bottom of the boat.Ran a little extra for safe measure.