Gotta concur with the above - I really liked my first CS-305 for occasional almost-safe one-handed operation and other feats, until it developed an erratic too-high idle while under warranty. Depot referred me to the authorized repair place. Six weeks later, it came back to me, with the repair tag and bag-o-parts telling me they'd replaced the plug/filter/gas-filter. Hell, I coulda done THAT... And guess what? Same crappy running.
Unfazed, I returned it with Depot's sympathy. I eventually bought another one, too, thinking that diagnosis might be easier if I had two - a good one to swap out known good parts from when needed, plus I needed a second lightweight saw for some extreme hillside work.
Well, one way or another, both saws ended up being run without air-filters - unintentionally - and sucking in considerable crap in that process. (It's easy not to see this condition, since the carb/air-box opening faces the tip of the bar on this model.)
When "saw A" did this, it quit running before I noticed the missing filter. I first sprayed out the air-intake box & carb throat with brakleen (volatile solvent-cleaner in a spray-can, but not specifically for carb-cleaning). I tried starting it, but no joy. I then pulled the carb out, looked into the valve and saw that, predictably, a little chunk of wood had lodged in there, keeping the valve from sealing. "Eureka," right? Got it back together after considerable futzing with a gasket that wouldn't stay in place, and repeating this carb removal/replacement to get the throttle-linkage working right, it fired right up. But since it was already well after dark and I didn't want to annoy neighbors, I stopped after just a few seconds of running, well-satisfied that my long-winded repair effort was not for nothing.
Next morning, I put a new filter on it and went to fire it up, still glowing from my repair success. Normally, full choke followed by two solid pulls gives a "cough of life," and then with choke off, it will start right up. This time too, the choke-cough happened, but on taking the choke off and pulling again - nothing. Back to THAT again?
Sweat-soaked and cussing up a storm, I gave up again, fifteen minutes later, and set the saw aside. No combination of throttle/choke seemed to do anything anymore, other than the occasional teasing choke-cough.
Saw B (identical) was still running fine... until yesterday. I keep it up on the steep hillside which I am slowly clearing of trash trees, and I had used it on a bunch of cuts the other morning...when I noticed, to my horror, that the filter-cover and filter were just gone. I had no idea how long that might have been the case, but the air-box was well-peppered with debris, the filter-cover and filter apparently having vibrated off at some point. Still, it was running pretty well, though the idle seemed to be varying and maybe too high. I fired it up one last time, just to verify that it was still going to run OK if I just cleaned some of the crap out and put a new filter and cover on it. It ran well enough, so I put it away for the day & my next trip up the hill.
Next day, I headed up the hill with a new filter/cover, and a can of brakleen, planning to spray out the air-box before putting the new filter in place. I sprayed it out, holding the carb intake lowest, to minimize the amount of solvent that might get into the carb (and perhaps momentarily affect running or starting.) I wish now that I had tried to start it first, but I didn't have any real fears about it not surviving the simple cleaning it needed...but suffice it to say that it is now behaving identically to the first saw - coughs on the second pull with the choke on, but beyond that, no life signs.
I am beginning to wonder if the brakleen solvent can somehow do more than I would have thought to harm something I would not have expected to be hurt by even the brief exposure...but that may be unrelated.
Anyway, what's a good diagnostic?
BTW, not knowing much about two-strokes, I was surprised to see that the intake on this saw leads through the reed-valve and directly into the crankcase...is this a typical design? On that same track, is it possible/likely that I've sucked in enough wood-chip debris to affect the bottom-end of these saws?
