Originally Posted by GMLC
Richard is 100% correct. Your hitting the rev limiter at full throttle with no load. Mine does the same thing.
So does mine, but mine only does it with the edger attachment mounted. It is nice and smooth at WOT with the trimmer head. I guess the trimmer head places a bit more load on it than the edger.
The one and only recommended valve adjustment is needed at 139 hours according to the ops manual, or as needed at any other time outside of that.