I'm back. Haven't gotten back to work yet.
No idea what kind of Chinese carb I have. The other two are Walbros.
As for the vent, my understanding is that they only let gas in, not out, so I don't think it's the problem. Perhaps this is wrong.
I have not looked at the screen. It should be okay. I don't think it explains why the saw suddenly went from working to doing nothing while being used very little.
I had no idea there was such a thing as a catalytic converter on a chainsaw. This thing has a head and a muffler. I haven't seen anything else in there.
I am going to try pulling only twice with the choke on and then disengaging the choke whether the saw barks or not. I have been waiting for the saw to make a starting noise, but these things flood so easily, I think it's a mistake. Also wondering if I even need the choke, since it's maybe 85 here. It already started twice recently, so there has to be something wrong with the carb adjustment or my procedure.
I have a new OEM carb on the way for the Jonsered. I don't know if I want to keep it, though. It's 10 times as hard to work on as the Echo, and there is no bar oil adjustment, so oil goes all over. It acts like it has an air leak, but taking it apart to look it over is a really bad experience. I could change an Echo carb in three minutes if I really had to.
I bought it because it was literally the only saw I could find after Hurricane Irma. I can use it right now, but anyone who comes near me while it idles is in a lot of danger.
I can get a couple more 5-Ah batteries for the Makita for around $155, so I would have 6 to work with. Maybe I should do that, forget the Jonsered, and focus on fixing the Echo for bigger jobs.
There is a Stihl dealer and repair place near me. I have not used them because they do Stihls, not Echos. Maybe it's worth it to buy a 60cc Stihl just to have a relationship with these people so I don't have to drive myself crazy trying to fix saws. I said there were no good mechanics near me, but I left these people out because of their Stihl business. Maybe they are not idiots.