Welcome,
It just might be time to go through The fuel/intake system from filter to cylinder. If this does not solve the issue then a compression test is next. 3rd would be a vacuum/pressure test to verify that there is not an air leak being introduced into the system to cause eratic operation/idle. A vac /pressure test can be done with intake and exhaust block off plates that are correctly sealed. They can easily be made with 1/4 " alum, plate and 1/4 npt barb fittings. An old school style vac/pressure fuel pump test gauge will handle the vac/ press verification duties. The vacuum source is under your nose. (insert joke here, haha) The spark plug must be well seated, a dab of grease will help seal it for the low pressure needed if in doubt. I'm not sure if the non special has a compression release but if it does I would plug it. I don't remember the thread count off hand. (10X1.? mm ) This issue has been solved hundreds if not thousands of times on this site. Spend a little time researching then ask what questions you are not sure about. Saws are not that complicated when broken down into the few simple systems that they are made up from.