I started to have issues with my 2016 9.9 yammi after 4 years of flawless trolling with it. It kept stalling on me while trolling. I read where they are set to run lean from the factory due to emissions standards. There is a small aluminum cap over the fuel mixture jet/screw on the carb. You can take a small pick and pry it up and off easily. Turn the screw to open it up a little. I have not had any issues since I richened the fuel mixture a little bit.