I had the smaller edger for ten years. After much satisfactory service I replaced the carb, to solve the problem of its dying on me. After some time it happened again and I tried another carb replacement but, alas, I couldn't get it to keep running. I sauntered over to my local Lowes and bought the newer version, the 525ECS. It's a nice machine BUT it's a lot heavier than the old one and worst of all, It seems to have super-compression bc I can hardly pull the starter rope. I manage to get it running but I am hurting my arm, big-time. There's nothing wrong with the rope mechanism bc I took it apart and also removed the spark plug; the motor spins easily with the plug removed. This has been the case ever since I bought the thing; I should have returned it immediately.