I know these engines tend to run rich. Sometimes inducing coughing/stumbling at full power, full rich. As expected, leaning resolves this. Pre-2014ish versions were improved via the carb sump insert and perforated fuel nozzle. My 2010, #122, was a great example of coughing before these mods and smooth running after.
2014ish models and beyond had that stuff built in as standard. However, my 2014, #307, still produces that coughing that is only helped via leaning. Switching from the Marvel carb to an Avstar seems to have helped some, but not completely.
What experience have others had? How sensitive to temperatures and altitude?
Thanks!
Andrew