Time for an anecdotal story I think!
I have been a member of a local dive club for 30 years and for all that time the club has used 2 stroke Mariner outboards on its boats with virtually no major repair bills. These engines are never washed out after use, get extremely hard use and have been totally reliable throughout. With all the advertising hype about 4 stroke OB engines promoting reliability, low noise, low emissions and good fuel economy both myself and my dive buddy of 30yrs specified 4 strokes on our boats. My dive buddy went for the twin Mariner 40 set up and I went for the 75 Mercury. We both wash out our engines after every trip have them serviced professionally every year etc, etc and yet this year we have both had major strip and re-builds required due to corrosion. These are on engines that are 4 and 3 years old respectively so from our personal experiences we are not very impressed and will be going back to 2 strokes.
I know it