Stewie1
Bronze Member
The way that hole is formed, something came from inside the motor to the outside. That doesn't look good at all.
I took the time to go look at my (garaged) B3200 this evening. I believe this model is an updated version of the B7800. From what I see, I don't think the hole is as a result of an internal problem, but is as a result of the idle throttle stop portion of the casting breaking off.
Here is a picture of my (hopefully intact) throttle control plate. Not quite the same angle as my loader arm was in the way!

My tractor is off with the throttle closed, i.e. at idle. Comparing our photos, I think your idle stop has sheared off, and this could also be contributing to the engine cutting out which was your original issue.
I am not an expert in these things, but hopefully the picture comparison will help. I would think that replacing the plate may be all that is needed, although some adjustments would be needed to get the new stops adjusted correctly etc.
Hope this helps and good luck with the repair,
Stewie