I have a borrowed cultivator (Echo TC-2100), and having hard time running it. It looks fairly new, and in good condition, but was possibly poorly stored and was not winterized.
At first I could not start it at all. I checked the spark, and it was weak, and, moreover, the plug porcelain jacked was cracked and ignition was shorting a bit (I was feeling it while touching the cable even in heavy leather gloves). I replaced it, the spark was sort of weak still (even in comparison to other small engines), but I was able to get it to start (not sure that could be the issue still).
Now I got it to the point where I can start it every time with choke on, but it would not hold the idle on choke for long, and otherwise, as soon as I drop the choke it dies, sometimes trying to stay alive. It would not idle, and would struggle and die if I try to throttle it.
This is emission-restricted model, so the carb adjustments are limited with plastic caps, and I had adjusted them as per manual (PDF). Other issues I see are a) primer bulb cracked and seem to leak air (how much of an impact would it do?), b) fuel filter can be clogged, and c) carb main jets could be clogged. I would like to understand the symptoms better, and find the cause before I start putting money into replacing parts for the unit that is not mine.