Futher update, the hole on the choke arm on the chinese knockoff husqvarna carb, is much larger than the original zama. However the choke lever does work fine with this larger hole. The only time the lever might come unhooked from the arm would be when pulled out to full choke. It makes the choke floppy when pulled all the way out, unlike the OEM setup. However once the choke is turned fully off, the way the rubber grommet holds the choke, the whole setup is very stable and should not come unhooked.
Next the real problem with this carb-which is easily remedied-is that when hooking up the throttle cable, the throttle is held open, meaning it is as if you are holding the trigger down a little bit, holding the throttle off of the tapered idle screw. At first I tried swapping the nylon throttle cable attachement point from the original zama to this knockoff. It doesn't work, it holds the throttle open even further open at rest. So I put the knockoff carb back together as it was shipped, and then took a very small file, and just filed back maybe .050" of the plastic where the throttle cable ferrel seats, the further you file back, the more closed the throttle becomes at rest. I filed it back enough that if I turned down the idle speed further from where it came as shipped, I still would be riding on the tapered screw.
Saw fired right up and to my shock I had to make extremly minimal adjustments to the carb, to get it where I wanted before getting into wood. At very light throttle just spinning the chain to get the oil pump going on a long bar, the saw does 2 stroke, most carbs I've found would be rich 4 stroking at this throttle setting. So the idle circuit off idle seems a bit lean, but still has good throttle response. I haven't gotten the saw into wood yet, so we will see how it fuels under load and how well it holds adjustments, I'll post back up.
As to carb mods although this carb does say "c3m" cast into the side, if you take off the metering lever cover, it does not have the two brass jets that you can mod like the twin jet zama that it is replacing...
