I changed to 4 stroke about 10 years ago. (Yamaha 100 carbureted) On all my previous motors (all Mercury 2 strokes) I always ran the carb dry just like my Dad taught me to when I was a kid. However, I have never done it on my Yamaha and have never had any trouble in 10 years. I think the 2 stroke oil is the problem especially if it sits in there for a while. (Think snowmobiles sitting all summer) Anyway another factor that I’m sure helps it that my boat stays inside the garage always plus I use it year round so the gas is never very old.