My china generator 5.KVA ,the motor side housing broke from the foundation , purchased a new one , the housing is placed in position and the 4 outer bolts are tight but 2 screws , which tight from the top (long ones, just like the outer ) won't tight. They rotate free.whats wrong ?or is there an inner plate which have moved its position.

I'm not sure we can help besides check to make sure the threads are not stripped. If threads are stripped, EZ-coils can be used to replace broken threads.

They may have nuts on the other end.