RE: SYSSA 30CC GAS MADE IN USA
Rob,
Using the TACH to back off the high speed needle until you note a loss of at least 300rpm. The 1/4 turn is simply a suggestion. And remember when tuning; the low and high speed needle interact to some degree with this carb.
Running the lil beast lean will cause and affect a cough as you noted, throwing the prop/spinner and even taking out the prop hub key....
Michael Glavin