Pinch the fuel line that goes to the carb when the throttle is all the way up if you hear a slight increase in rpm its rich if not its lean you can do this test on both the low end and high side. Run your throttle all the way up pich the fuel line and if the rpm increases a little lean the engine if not lean a little just untill your hear a slight increase and stop, do the same for tghe low end and you should be good.