your 670/6700/8000's were a different breed of cat than mine. i haven't run the 8000 yet, waiting for an air filter, but mine have wide power curves with ample torque. they don't spin as fast but once the find the rpm where max torque lives they'll stick there tenaciously. these are characteristics described by quite a few who use theses saws. makes me wonder if there was something wrong with yours. yes, the little 59.8cc echos are different, sort of a toyota to an f250. i like the look of the clutch/oil pump drive. but 60cc saws just don't do it for me, not there's anything wrong with it. i'm glad that echo is still selling the 680 and the 8000. there's still a small market for a high quality workhorse. for most weekend woodcutters the 60cc echos may be a better choice. lot of the hombres around here use poulans and 029s... not me.I've owned two CS-670, one 6700 and an 8000. They all have the same power characteristics as well, somewhat narrow power curve and pull very easily out of the good power and stall against the clutch. The 6700 was the worst of the three and it had a new P/C on it.
I exploited them for a while then gave up and put all of them up on Ebay and moved on. The CS-590/600/620's are a completely different animal, with very impressive high rpm power and broad/smooth power curve. I ran both of mine yesterday cutting HUGE oak and Beech logs/stumps and they never grumbled one. Just for kicks I used the 600P to cut off a 40" wide Red Oak stump and had the bar completely buried the entire time and it never stalled once against the clutch.
Then I used both saws to cross-cut the huge pieces to make them manageable........Cliff
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