Zama versus Walbro carbs, some of the 2165s had Zamas that could be fussing on tuning without much ability to fix. Lots of ideas for fixes but the best solution was to replace it with the Walbro carb.
Basically a lag, if it was real bad the engine would sound like it was going to stall when throttling up to WOT and when it was severe the engine would die after when returning to idle from WOT.
Squeeze trigger, almost stall.
Release trigger, almost stall.
If it was a bad carb, the saw would stall, especially when cold. Tune the saw and the next day it would need to be retuned.
I have one of those Zamas on the 365 that I currently using. Replaced metering level spring and it was improved but still stalls occasionally when returning to idle.
Starts back up instantly with maybe as little as a quarter tug on the starter every time.
Too much TURBO for the Zama.