Ouch.... one of my piston pin retainer clips is bad, I'll need to get one for my 239Y somehow, I know we could maybe find something that would work but ... I think it's a lot better to use the real thing.  I'm sure all Y-block clips are the same size, If somebody has an old one laying around tape it to a piece of paper, include your name & address, send it in a simple envelope, I'll return a crisp 5 dollar bill to you ASAP, depend on it.
Thanks much,
Warren Sjoberg
14942 62nd Ave.
Milaca, MN 56353