This is the back of my engine, the screw I'm talking about is the retainer screw in the recessed area in the middle of the backplate.. I guess it would be called a back plate... On mine this screw is a right hand thread screw... Hmmm..
The hole in the middle of the 4 screws holding on the backplate is the one I'm talking about,, the screw is recessed in the bottom of there...