Hi I have 2 shindaiwa t272x -- i was going to sell them now that I've discovered STIHL FS90R -- half the weight, nearly half the price, half the noise, almost same power as t260. But one of them is running boggish -- will run well on half choke -- so I brought it to mechanic, but was up to $70 in labor and hadn't found problem, so I took it home, ordered brand new carb, thinking that is what i should automatically do from now on the minute a 2 cycle machine without mixing screws runs boggish. But after swapping carbs ($60) it's running exactly the same. I have already bored out the baffle, scraped the exhaust ports, etc. etc -- and I'm PRETTy sure I changed the in tank fuel filter ... maybe I should do it again just to be sure ... and I use ECHO 50 to 1 oil .. anyone have similar problems with shindaiwa or other trimmer -- where symptoms said "carbuerator" but it was something else? Any ideas would be AWESOME -- I've decided to keep these till' the end, just to have backups and I'd like to keep them up and running smoothly. Thanks!!