Understanding Diesel fuel with my sub compact tractor in winter.

[CADplans]

So why do some machines have dual filtration and water separator and a machine like my Diesel Steiner has one junky cheap in-line plastic filter? My Onan Diesel gensets only have one filter as well.

Shouldn't the highest level of filtration apply to all diesels equally?

These filters are so cheap,, why not add them, and be happy?
Here are the two filters on my 2013 (year model) Yanmar powered tractor.

The silver round thing mounted with one bolt is the fuel pump.
It is easy to see the fuel flow,,
from the tank to the first filter, then to the pump, then to the second filter, then to the injector pump.
excess fuel goes back to the tank.
The excess fuel is necessary,, it cools the injector pump.

 

[ForestGrump]

Just kind of a side note on diesel quality. I am told, that the clearances of an injector pump are so tight, that parts warmed in your hand will not fit. Water will (potentially) ruin injectors and pump.

So why do some machines have dual filtration and water separator and a machine like my Diesel Steiner has one junky cheap in-line plastic filter? My Onan Diesel gensets only have one filter as well.

Shouldn't the highest level of filtration apply to all diesels equally?

Diesel is a "wet" fuel. The more fuel you burn the more water goes through the system. The bigger the engine the more fuel you burn. The manufacturer chooses the filtration system. Jet fuel is wet, they run it through a clay filter to polish it at the refinery.