The LSN is the Low Speed Needle.. You should try the pinch test anyway it could save you a lot of time... Besides Hobby shops are notorious for bad tuning .. Ok Drag as it was mentioned will have to do with how the clutch bell rolls freely and indipendantly from the clutch shoes inside.. just roll your car along and notice if the clutch bell rolls freely without making the flywheel turn.. the flywheel is the thing that the clutch bell is attached to.. If it makes the flywheel turn as well you have a problem.. You may also have an airleak in one of your fuel lines.. is the carb bolted down well to the engine .. ie any movement when you try to twist or juggle the carb ?