New Generac GP3000i wil not run unless tipped

I have a new Generac GP3000i that will not start/run unless tipped to the side.  I assume its the oil sensor; however, the low oil light does not come on when put back to level.  It just shuts off.  I have disconnected what I beleive is the oil sensor wire coming out of the engine block with same results. If it is the sensor, how difficult to replace? Any other ideas...?