Primary fuel filter sediment

[Robert Moretti]

I have a Dahl primary fuel filter on the Universal M-25 diesel engine in my Catalina 30. I was inspecting it the other day, and could see visible sediment that appeared like soot on some of the surfaces in the glass bowl. I'm new to diesel engines, and don't know whether this means I need an immediate filter change. The engine is running perfectly.

 

[harvey]

Dahl filter

No you don't have to change it now, but it may mean that your fuel has some problems. The best way to guage it is with a vacuum gauge. But what I would do is pump most of the fuel out using the electric fuel pump and replace it with new new fuel using a biocide and perhaps a diesel treatment product. Then you can replace the filters. This is especially true if you don't use your engine very much. Try to get your gas from a reliable vendor who does a lot of volume.

 

[Jim WIllis]

Polishing fuel

Never had it done (my fule with biocide seems good after years, although I keep it topped up.I understand that there are people who come to the boat and pump the fuel through a fine filter that removes all the crapProbably someone out there has more details.