Sounds like that washer is the shield for the needle bearing piece of the assembly (officially named the thrust bearing). Check out the exploded view here: http://www.noramclutch.com/go-kart-clutch/premier/titan-sp2.html
That was the drawing I was going by – if you’re talking about the thrust washer, that’s not it. This piece had a large enough ID (and was much thinner than the thrust washer) to almost slip past the spiral snap ring holding the sprocket to the drum, and didn’t really have the right dimensions to locate any particular part of the assembly.
