Most carburetors on the 2 stroke trimmers are all the same. They are of the diaphragm type. I would like to send you to a tutorial/information tuning page for this type of carburetor. If you do choose to adjust it yourself, pay real close attention to the before and after settings on the screws you turn. These carbs are extemely sensitive and respond likewise. I use an automotive type plastic wire connector lightly tapped down onto the unconventional heads of the L and H mixture screws to turn them. The plastic on the connector will expand a little and grip the screw head to allow you to turn it without any damage to the screw. Please view this tuning guide.
http://www.zamacarb.com/tipspage.html