You guys are all amazing! I don't think I can respond to everyone all at once
Thank you for all the pointers. I bought some Permatex valve grinding compound and cleaned the seat; that q-tip baaaarely fit in there. I'm using the replacement needle as well.
So here are the results (so far anyway):
That's a bit fuzzy but you can actually see the shine off the brass in the valve seat now. I also used a dental pick to clean out the area around the opening and then hit everything with carb cleaner *a bunch* to try and make sure that none of the compound is still in there. It looked clean when I was done.
Here is the re-terminated end of the grounding wire attached to the carb body:
I mashed down on that ring terminal with my lineman's pliers and it crimped on there quite firmly. Looks a bit festive.
Also, here is the assembled float from the side; you can see that it is pretty much horizontal. It's a plastic piece and it seems like it's in decent shape so I don't think it's a part of the problem. We'll see
The float has the new needle attached to it, so hopefully that will help as well.
Then I mounted the whole thing back on the mower and secured it on the studs with the nuts that actually hold the back plate for the filter box. Reconnected fuel line as well.
The picture is actually cropped out, so it's a bit fuzzy. I put a little gas in it and left the garage about 15 minutes afterwards. I'll go check it again to see if it's sealed up! I hope so...
Fingers crossed! If that worked then I have to double check the throttle positions. I totally dorked around with the governor before I knew what I was doing (the throttle plate won't close at low throttle position because... governor duh...) I followed the advice in the service manual for resetting the governor but I may have to get that dialed in. I have an induction tachometer I can use to test the engine speed if things aren't working quite right. Just want to avoid an overspeed...
Anyway, more to come! Thanks again all