Chainsaw Repair

Update:

I cleaned the cylinder up, replaced piston, new fuel line and filter, carb kit, and its back together. Pressure and vacuum test passed. Carb passed pressure test too. Compression pre-break in is between 145-150 psi.

I haven't dialed in the tuning yet. It still died a couple times when I let off throttle during tuning. Hopefully its just a tune issue, but if not, it seems like something with carb internals is wrong that the rebuild didn't fix? Check valve held against vacuum too. Replaced welch plug (no nail polish). I feel like i've eliminated virtually every other problem...

unless ignition could cause this?