I found a service manual for the saw.Okay.
Have you checked the ignition coil to flywheel gap? Too much or too little gap can affect ignition timing and cause issues like yours.
Problem is I'm having a hard time finding the spec. 0.008" to 0.012" seems to be in the ballpark though.
Air gap between ignition module and fanwheel: 0.15 – 0.3 mm
I need to get a new set of feeler gauges but will do so and make sure it is correct.