What you have encircled in red, is not the main jet. It's the valve seat, where the float needle's conical tip controls the fuel flow. The valve is supposed to have just one O-ring, in the middle. The main jet is also supposed to have just one, rather small, O-ring. See pic below. The main jet sits right under the needle jet (aka emulsion tube). The end with the O-ring is supposed to be up. The groove on the other end is to accomodate the springleave that keeps the main jet pressed in position, once the float bowl is put on again.
