I sandblasted and in the process of repainting the same machine as you. I am trying the Rustoleum Old Cat Yellow. That stuff was really hard to come by last summer and only could find quarts. I am mixing it with some acetone, the cheap Magic Hardener from Tractor Supply and a cap of Japan Drier. (Found a recipe on youtube) Seems okay so far. The tractor sat out for a month last summer and is currently sitting outside the past month or so. I painted the engine the same way and so far it is holding up to diesel fuel running on it when we had trouble getting the fuel tower to seal properly. First time really had trouble but go figure.
The jury is still out on the Rustoleum. I would have used some Polane urethane paint from Sherwin Williams but they couldn't get the correct colors last summer but I would rather have used it since I paint a few jobs with that stuff that's in the weather.
There was another topic on this subject about a year ago and someone found a paint company that has a match as well but can't remember the manufacturer.
There are several on Youtube but I tried this recipe:
https://www.youtube.com/watch?v=6eoFYTp98XE&t=682s