Small Engines (Lawn Mowers, etc.): Homelite Backpack Blower, backpack, screw

Question
My Homelite BP250 backpack blower is almost impossible to start.  When it does run, it stalls repeatedly and won't run at all on the highest setting.  The plug, gas and filter are all clean.  Help!

Answer
carb. needle settings. there will be 3 to adjust.  to get started,turn the ones on side of carb.  in lightly til they stop.  back out each 1-1&1/2 turns each.  there will be a (L)  next to one and a (H) next to other.  the third is on top of carb. which is idle screw.
when it is running at high speed adjust the (H) and at low spead adjust the (L). idle will be adjust til it stays running.