Just dug into their site a little, haven't been there in a while. Looks like their minimums have gone up. Looks like the 9/16" keys are special order now which they weren't then.They used to have them by the each.

Oh, and Congrats!

I would recommend replacing both pieces that way you can be sure they are matched. Also, if you look at that PDF I linked you will see they make assemblies that are designed to go on in the orientation yours was but are removable without brute hammer force. Unless, if you have enough room to align the generator and engine in a manner that will allow you to use a standard bushing and pulley which will likely be cheaper and more readilly available. How long is the generator shaft that you have to work with?

teems like I definitely need to try and get the pulley to move IN first, something I didn't try much, as I didn't really believe it could be on backwards.

No, you want the pulley to move out, as in separate from the bushing. They are tapered inside so the closer the pulley is to the flange of the bushing the tighter it is locked to the shaft. The bushing is not going to move on the shaft until you get the pulley off which means it needs to move away from the bushing flange and generator. You may be able to get a large enough puller in there but looks pletty tight.

Here is a link to a diagram and instructions pdf.

https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.martinsprocket.com/docs/catalogs/power%2520transmission/3_bushing%2520catalog/qd-bushings-catalog.pdf&ved=2ahUKEwix-_Dy3qL-AhVbEFkFHSDaAwgQFnoECBIQAQ&usg=AOvVaw3T-3NYNMyBNBV6oco_5WdS

That's a taper lock bushing and sheave. Whomever assembled it put it on backwards, most likely for alignment reasons. There should be two threaded holes in the face of the bushing(the inner part)(facing the generator), they are "jacking" holes. Usually one would just use two of the bolts removed but since your bolts are captured you would need two bolts the same size but short enough to fit between the face of the generator and the bushing. Screw them in and they will force the pulley off of the bushing. You don't have much room so may have to get creative with sliding washers between the bushing and pulley to work it off. It is a taper fit and would be very difficult to drive the bushing in. Usually when I come across that I just cut the pulley parallel to the shaft so it will come off of the bushing and then pry it off of the bushing. Once the pulley is off it releases the taper lock and the bushing can then be removed.

You are correct, the belt drive piston pumps use SAE 30 oil.

Nicely done! Another one saved. Congrats!

Nice looking set up. Good luck with the sale.

Coming along nicely.