Small Engines (Lawn Mowers, etc.): Echo back-pack blower, tank fuel, spark arrester

Question
I have a an Echo backpack power blower model #PB413H, ser# 09055946.  It starts up OK but when I "give it the gas" it hesitates, may or may not speed up, and usually stalls.  I've tried the following: 1) emptied gas and refilled with fresh 50:1 mixture, 2) changed in-tank fuel filter, 3) sprayed carb cleaner, 4) cleaned air filter, 5) cleaned and regapped spark plus (.026) 6) cleaned spark arrester screen, 7) took off muffler and cleaned 8) added "Sea Foam" carb cleaner to fuel mixture (per Echo's recommendation).  There's been no significant change.  I've noticed though that if I play with the choke a while I can get it to throttle up, but it doesn't reach full power and after a while may start to power down on its own. It will only continue to run when the choke is about 1/2 to 3/4 open.  Your thoughts?  If you think it's the carb., can you offer me any links to sites that might walk me through the repair process.  Thanks.
Len

Answer

carb Len
Yes it is a carburetor problem sounds like a jet is clogged with some kind of blockage.Here is a parts breakdown on the carb,if you need a rebuild kit let me know. You can e-mail me at gb@gbelect.net or visit our on line store at www.gbelect.net for parts.The rebuild kit is # 12530008360 and the carburetor # is A021000890