Inglis MOD#IPU58460 Dishes not

Question

Inglis MOD#IPU58460 Dishes not cleaned properly...thought that enough water was not being filled into tub because more water added manually and washes great! I checked inlet water valve operation and lines for possible lime buildup and timed "fill" time. All was good and time right to spec! Water level after fill is just to bottom of mesh screens. Under further trouble shooting I held door open slightly while holding door switch closed to observe wash cycle and found as pump starts water shoots up at center of bottom wash arm and arm only shoots little out spray hole and turns slightly than stop as pump seems to lack water and than repeats this over and over again which would to me explain the poor cleaning. Could it be possible a part or seal is missing where retaing nut holds washing arm in place?? There is the plastic bearing clip under the wash arm and a smaller plastic ring clip on top under the retaining nut which do not fit tight together. There is 1/4 inch or more play or movement of wash arm and maybe this is normal, I am not sure. What I am trying to say is I think so much water is being lost up the center of the arm that the pump looses pressure or prime and starts again once enough water returns to the bottom of the tub and than this cycle just keeps repeating itself. If you have any suggestions or answers for this problem it would be greatly apreciated! Thankyou, Bryan.