If that 041 uses the late black SEM GE module, and if it still won't spool up to speed or still backfires after your air leak repairs, then the SEM module is faulty and needs replaced. Good luck with finding a new old stock one as I never did.
The "backfiring" & low RPM was the exact issue I had many years back with one on my Super 041s, and when it backfired at idle it would sometimes stall & then restart itself to run the chain backwards! That could quickly destroy the starter if the rope handle was bumped or pulled out.
Replacement with a good used SEM fixed it, but I'd first suggest putting an inline spark tester like a ZAT4 on it & watch the spark die out when you fully open the throttle.
I wish I would have taken a video of that saw running the wrong way... could have turned it upside down and cut wood with it, Lol.