It could be worn components causing drag, but typically that will cause constant drag and not intermittently as you noted here.
It sounds more like a misfire issue. That could be due to the timing being off for some reason, possibly a loose or mis-positioned coil or a damaged flywheel key that allows the flywheel to position in the wrong spot.
The engine also could misfire due to poor or contaminated fuel or an air-leak or carburetor issue. And if the cylinder or crank were worn they could also create issues with starting.
Another possible problem area could be too much back-pressure caused by a partly plugged exhaust. That can happen over time on 2-cycle exhausts as the unburned residue from the premix oil collects in the muffler and can eventually cause restrictions.
Checking the parts illustration in your
or at the
site will give you some idea of how all the components fit together and some of the potential problem areas.