I would have to suspect something with spacer 24 or washer 27.
Make sure both are present and that you did not mix them up.
On the one-speed, the washer has a round side and a flat side, and it makes a difference which side faces in/out. (flat towards center of engine.) I would think that the two-speed might be similar.
The nut has to be torqued to about 200 inch pounds...(168 - 224 inch pounds?)...best to use a torque wrench here.
Make sure the rubber nubs and disc are facing the correct direction..."rubber ends should face towards the outer side of the engine and the thicker lined face of the disc towards the inner side of the engine."(edited)