Splitting the tractor is about a 1-2 hour job if you've never done it before. At least it is on a WF. I can't imagine a NF would be much harder?
In regard to your dying condition, I would still recommend you check for spark while the motor is HOT and work backward from the plug wire to find what the problem is.
Otherwise, good work and thanks for the pictures! Working on my neighbors green mower is getting me down so it's nice to see yellow again
