Piston ring ?

[cfish]

In my Tecumseh I was installing my piston and broke a ring is there a way to figure out the size of the rings besidess using a boat gage . I don't know if its standard or not
Tecumseh ohv155 204502a

 

[Rivets]

Look at the top of the piston. If you do not see .010 or .020, it will be standard size.