Miriam,
The clutch bushing does come off rather easily using a puller, but first remove the tapered pin or screw that goes through the bushing into the mainshaft. I have removed and replaced several of these.
If I understood your previous post correctly, you are going to put the spartan into the 66's case. It won't work the 66 is full size and the spartan is 3/4 sized.
Cathy