Hi Norm,
I had a look at a 10 /11 hp briggs and the stator bolt is the same as the bolt that holds the coil.
I don't have a thread gauge that goes that fine ,best guess is it's 5/32 bolt 32 TPI
and (1 inch long measured under the head to end)
Usually if I'm not 100 percent sure I'd buy a bolt that size and try it and if it's right
buy the tap.
Cheers
Max.