I know that Ive only had 2 Echo's come in that were beyond repair.
One had been used commercially for a year with no air filter installed, and one had been run on straight gas. Both blew 70psi, and started easily, and ran fine, but bogged when they warmed.
Customers bought new ones without a 2nd thought.
Boss said that at an Echo "expo" they took 3 NEW identical SRM-210's.
Taped the throttles wide open on all 3.
the first one they tapped the air vents up, all over, they went through a ton of tape making sure the thing couldnt breath. Filled it with 50:1 mix gas, Echo power blend.
The 2nd one was filled with 50:1 mix of gas/ sae30 motor oil.
The 3rd one was filled with straight gas.
All 3 were cranked and set outside to run with line installed.
They all ran out of gas about the same time, 1 tank...Then they were filled a 2nd time...the first 2 ran the whole time they were there...only stopping momentarily to refuel. The 3rd one seized after 2 tanks. IT cooled, unstuck, and refired, and ran through a 3rd tank...and seized. Cooled, refired and ran through a 4th tank, and seized again.
All in all it seized 4 times...the other 2 kept running.
After it was all done, they compression tested all 3, and the first 2 still tested at new compression levels. The 3rd one was like 130.
As they were leaving they offered the 3rd one to my boss "if he wanted it"...so he accepted.
He took it, pulled it apart and found a mildly scuffed piston...he put it together, added mixed gas, and we are still using it to trim around the shop every week...runs like new with a ton of power, just like a new one.
Echo Trimmers are some tough SOB's. just like their saws, which dont get any love.