This past winter when starting my N-14 it was very sluggish building oil pressure.  In fact, on more than one occasion, it would shut down due to low pressure.  A secondary problem I have is the oil pressure gauge is not working properly.  After starting and running at low RPM's revving it up to about 1,500 RPM's pegs the oil pressure gauge and that is where it stays no matter what RPM's the engine is turning.  Do I need to be looking at replacing the gauge, oil pump or something else?