tuning indications of "fat" mixture

[Bugsy]

My 49cc two stroke "four cycles" except at a couple specific RPMs on level ground, but runs perfect when climbing a hill. Am I correct in thinking this is an indicator of a rich mixture?
The carb can be leaned a little by moving the needle down in the needle holder to a notch closer to the top end of the needle. Is this correct?
Thanks, Bugsy

 

[sparky]

Sounds about right.

Check the plug and see what she looks like.