5020 stinky exhaust

This one is more of a "meh" issue but I'm wanting to know if this is common.

In my limited experience with small diesel tractors; the exhaust has a certain smell.

To me it was always a somewhat pleasant smell; almost sweet smelling.   I never found it a bad smell.

So I kind of expected the same out of this little tractor.   There is no reason for me to think it is burning excessive oil.  It cold starts right up usually without the aid of the glow plugs unless it is really outside temps.  There does not appear to be excessive blow by pressure from the vent at the top of the engine.  It does not smoke in any way or appear to use oil. (has 1100 hrs on it total).   But the smell of the diesel exhaust is not the same as I was use to.  It is more of a oily smell which is unpleasant.  

Now maybe I'm missing something here.  My point of reference is mostly when I help my dad with his farm equipment business back in the 80s.  We would take trade in on small diesel tractors all the time.  Kubotas, Mitsubishi, Kioti, and lots of Ford tractors.  The diesel tractors always had that same  sort of pleasant smell to the exhaust.   So as odd as it may sound I'm sort of missing that in this tractor.   

Is that diesel fuel has changed since those days and now has a different smell when combusted?  

Could it be the injector pump may need to be tweaked for a leaner burn?  (no idea).  

Any input would be appreciated.