Well, this spinner is fishy. I wouldn't be that suprised its thats the one causing these problems.
I've talked to a couple of people and no one have never even heard of this kind of construction.
I'll try too explain, but since english isn't my mothertongue there will probably be a lot of "thingys"
and "whatnots" instead of the correct technical term

The spinner comes with a back plate, front cone, two screws and four plastic bushings (?)
-> ( http://www2.gpmd.com/image/d/dubq3680.jpg )
You fit one of the bushings on the crank shaft (four different inner diameter-sizes so you won't have to drill the back plate)
and then press the backplate on to this bushing, then comes the propeller (which is tight I have to screw mine on, is that good or bad?)
then the spacer, then screw the nut tight. And then you press and screw the cone on to the backplate.


I'll report back tomorrow if the change of spinner and prop proved to be the solution to my problem. Thanks for the tips