the pinch test is how you adjust the low end.....pinch off the fuel line to the carb if the engine dies right away then the low end is too lean....if it runs on forever then your too rich...if however if it runs for a few seconds then revs and starts to die let go and it returns to a nice idle thats where you should be..now adjust the high end...go to full throttle..adjust the high end to max RPM by sound..then richen it a quarter turn..
Good Flyin
PS the best way to adjust the engine the first couple of times is with some help from an engine guru