G runs like crap

Carb - my throttle plate looked ok, but on closer examination it was worn.
The fuel level was off even though I set the flow depth correctly - the best test is to connect a piece of clear plastic hose and fitting to the drain cock on the bottom of the fuel bowl and observe the actual fuel level with the carb assembled and mounted on the tractor.
- I removed ALL of the plugs and completely stripped the carb down, then had it "tanked" by an engine shop, then I used the long bits to clean the passages.
Then I checked with compressed air to make sure that every 'circuit' inside the carb was clear. - Are you getting a pencil-lead diameter continuous stream of fuel for 60 seconds when bowl drain cock is wide open.
- did you remove the nozzle and carefully check that all of the small holes were clear.
- are the throttle bushings and shaft a close fit.
- The hole in the throttle lever that takes the throttle shaft was worn oversized and egg shaped. I carefully enlarged it with fractional and number drills and fitted a bushing made out of extremely thin-walled tubing that I bought at a local hobby shop.

Fuel - is the fuel fresh, and treated with stabilizer?

Air Cleaner - is the air cleaner serviced and completely clean.

Plugs - I tried hotter Autolite plugs which worked for me.

Wires - I replaced the wires with new solid core wires.