Congrats on the new mower, love getting new toys!
Next time you have the same issues you were having with the Makita, consider checking valve clearances before you write it off. Flywheel key is a good guess but out of whack valves can wreak havoc…
Maybe I’m not understanding what the problem was but, all I did was secure the blade from moving (wedged a log underneath the mower) and taking the flywheel nut off was a breeze.
Getting the flywheel itself off has been an ordeal, yet to be finished.
Same mower, same problem. As ‘Rivets’ says, check the coil. I just replaced mine yesterday and all is well. FYI it was Toro part #595959 and cost me $40 at a dealer.