Still enjoying these posts, Dave.
Not that doing a compression test is any "trouble." But before you go that far, are you certain that #3 has spark? A quick grounding of the plug and spinning the motor might save you some "trouble" and lead to a simpler solution. Might have bad plug wire or even a bad plug.
Can't remember if you ever talked about checking/setting valve lash. That might be another easy check worth doing.
