My name is Paul I live in upstate NY. I have a John Deere x300 and it doesn't work
First of all let me say I know what a wrench is but obviously I am not a bonafide mechanic. As I said I have a JD x300 42" mower w/100 hrs that I have been using right along with no issues at all. Last cut was 2 weeks ago. I went out yesterday and it would not start I used my trusty spark plug tester to confirm there was no spark. There was gas as pulled the plugs to see if they were wet. I checked 3 fuses they were all good. I do know that there is a safety interlock system that tells the engine not to spark or stop sparking if things are not right. So I disconnected the black ground wires to the two coils and walah engine fired right up. I put my foot on the brake and turned the key off and (suprisingly} the engine shut down. I started it up again and got up from the seat (with the brake off} and it shut right down, as it should. (although I don't understand how this could happen with the coil wires disconnected}
I started it up again and went out to mow. That is when I discovered the PTO/mower blades would not engage, I put her back in the garage and revved up my puter.
But not knowing as much as I probably should, I need a little more help and was kinda hoping someone could tell me what I should be looking for and where I might find it.

An example might be:
What has to happen for the PTO to engage? I am thinking PTO lever activates a switch that confirms or not whether a ground is present then goes someplace else?

On startup with the ground wires attached to the coils. What are the somethings that could tell the coils not to spark.

I was thinking if someone could educate me on these functions - that would point me in the right direction.

Thanks for putting up with my short story,