Dear All

I have a kit SP120. When I try to assemble this engine I experience some trouble. Actually, when I try to tighten the nut in the impeller side, my engine has some difficulties to turn. It does not sound like it is rubbing, but something stops it to turn around smoothly. After I torque it more then it relaxes and starts turning as expected. At this point, what is the required torque amount for tightening the nuts?

My other question is on small O-Ring installed in Diffuser. I could not solve the role of it. Why do we have these O-Ring over-there? What is it sealing? What happens if I assemble the engine without it?

Thanks,

Bulent Candan