Need some propellar help

I recently came across an aluminum propellar at a flea market that was supposedly made for my Yamaha OB ('96 115 4C). I had been needing a spare prop, the dimensions were what I wanted, and it was inexpensive, so I grabbed it. However, I am finding that I know a lot less about props than I need to. My primary prop is a stainless, and when I remove it, there are no washers or spacers of any kind. This is the only prop I've ever had with the boat since I bought it 5 years ago. However, the aluminum prop is a bit smaller, and needed a prop nut kit in order for it to fit tight on the shaft. The part that is confusing me is the thrust washer. I have no idea if this propellar needs one or not. The Yamaha owners manual clearly shows a thrust washer in the section that describes removing and replacing the prop. But with the stainless prop not having one, I'm just not sure what to do. I don't want to damage anything by running it without a thrust washer, but how do you know if you even need one? I tried to see if there was a manufacturer name on the prop so I could look it up, but I couldn't see one. Only the prop dimensions are stamped on it. Any advice? If I do need a thrust washer, where do you find the right one? I have to admit, I'm having a hard time finding them on the web. The sites that do have thrust washers, I can't tell which one could be the right one. I tried looking up the part # off the Yamaha web site, but couldn't find it.

Thanks in advance.

The thrust washer is probably stuck in the SS prop when you took it off, I never heard of Yamaha props intended for use without the thrust washer.

If you run the new prop without , it'll chew up the lower unit.

As for thrust washer kits, there use to be some @ ebay most of the time , around $30. Usually marked as "for Yamaha 70-130HP"

Exacly what are the prop markings, where are they, and which color is it? Yamaha props are often marked with a number and a letter , e.g 17-K whick means it is a 17" pitch propeller for the intermediate gear case.