oh! it is a 2stroke (3cyl) 15 spline which makes it post 91 i think, but don't know by how much. i have not got the engine or its details to hand i just thought (hoped) that the prop size would be stamped on the prop somewhere, otherwise how do i tell what pitch it is?
it differs a little between props, some is printed on one blade , some in the hub. The markings also differs , e.g. from full "3x13.25x19K" to just "17K" <br />The letter designates the prop shaft and hub size.