if your back pack is hard starting have you cheaked the price of a china carb i can get them for £7 to 9 my echo hedge trimmer was playing up started run fine but after runnning for 20 mins would be hard to re start if i had to turn off and would run a bit ruff after again 20 mins
bought a new china carb been running great for the last year and a half
when it comes for a service instead of a carb kit i will just order a new carb as its just as cheap
I have done that before too.