Yanmar 2GM20F also. And yes, it is a dumb design. The speed seal does fit, but make sure they know whick pump you have if you decide to order.

** IF ** I remember correctly my pump has an "O" ring in it, not a paper seal, so the Speedseal cover I got does not have an O ring in it. I'll have to look next time I open the engine up. It's preserved just now and I am working on rigging and electrical as Jill sews.

Greg