In some places this is not considered good practice. The solder can 'cold flow' under the screw and become loose, or intermittent. I marine practice this is considered bad because the wire will develop a hard spot at the end of the solder and strands will break there because of vibration.I also have a tiny solder pot (again very cheap) where the ends of the wire are first dipped into fluid flux and then into the pot, this again helps prevent the broken wire syndrome.
Hope this helps
Check that a welsch plug has not come adrift in the carby. They don't punch them in, just use glue. I took my son in laws not running whipper snipper home because it would not run and that was the problem. They say to use nail polish but I had none so made do with some locktite retaining compound and a gentle tap with a punch to seat the plug. I was amazed at my trouble shooting skills on that one.I lied. One more distraction. Fought and so far have lost against my gas trimmer today. Will only run on full choke.