Hi Steve,
I went through my "greenies" today and came across a parts engine that has the back plate, but is missing the drive washer, needle valve, and all the head screws are missing. Any interest in the whole engine or do you just want the back plate and screws? Send me a PM with an updated email address or a cell number that I can text photos to and get those to you.
Type at you later,
Dan McEntee