I bought a PJ-81 prop for my '72 or there abouts Johnson 50hp. The 14x13 oem has a thrustwasher on the inside that fits into the prop bore. It does not fit inside on the PJ-81, it would if the rubber was moved in further. Do I still use it or what? The shaft does have a taper so something is required as the PJ-81 doesn't appear to have the slight taper in it. The spacer is nylon. What should I torque this to?