for right now lets just adjust the high end....richen the engine up some (loosen) now lean it out and you will hear the RPM increasing...it will get to the point that it peaks in RPM and starts to decrease again...stop this is too lean...slowly richen it back up you will hear the rpm peak....stop..now if this is a new engine richen it up 3/8 of a turn..if its an engine that has been broken in the richen it 1/8 to a 1/4 turn....you richen the mixture back up to counter the tendency to lean out in the air
If this doesn't work we will try some other things