We believe in stopping contaminants as far from the engine as possible. For us, that's the Racors that are first in line after the tanks. The next filters are the two on each engine. After them, it's the injection pumps.
So on the advice of our diesel shop and people we know in the marine propulsion and generator manufacturing industry, it's 2 microns all around.
Another very good point has been made here that has actually never occurred to me. And that is the ease of changing the filter elements in the Racors. An added plus for us is that in our fuel system, which uses only gravity to move fuel from the saddle and day tanks to each engine''s lift pump, changing a filter element in the Racors does not require bleeding the fuel system. Changing the spin-on filters on the engines does.
So on the advice of our diesel shop and people we know in the marine propulsion and generator manufacturing industry, it's 2 microns all around.
Another very good point has been made here that has actually never occurred to me. And that is the ease of changing the filter elements in the Racors. An added plus for us is that in our fuel system, which uses only gravity to move fuel from the saddle and day tanks to each engine''s lift pump, changing a filter element in the Racors does not require bleeding the fuel system. Changing the spin-on filters on the engines does.