Hi Sapper,
              That is the spacer ring the 4 strokes use but it is no good for the PT application because the hole spacing does not fit the PT. There is a plastic ring that has 3 steel spacers clipped into it. I have a number of those but Aus Post will never get another cent from me posting things because they are just thieving bastards.Without the ring it will leave a gap but it won't cause a problem, might just let a bit of grass through