Thanks JG,
I used the shaft that was on the front of the engine for the prop adaptor.
The front half of the shaft was a square hole that the drive for the weed eater spool slipped into. I drilled that out and tapped it to 5/16 x 24.
I found an exhaust stud that was 5/16x24 on one end, smooth in the middle and 5/16x18 on the other. Screwed it into the shaft, found two thick washers and a nut.
Hopefully this will work.

Mark