mrsrobinson
Well-Known Member
Ok, this makes sense, and helps. I am glad I asked. The "flow" of fuel makes more sense now as well.Yes, you are missing something.
The reason Caterpillar says to only use the priming pump to fill the secondaty filter is because they only recommend using filtered fuel. If you pass the fuel thru a Cat high efficiency filter the fuel is filtered to about 5 microns. If you use typical unfiltered fuel to prime the engines then God only knows what size debris you are pouring into your engines. In my case, our marina only sells Valvetech treated and filtered fuel. The filters are 2 micron filters and there is a date on the side telling you (if you want to check it) when the filter was last changed or serviced.
My advice is to only manually prime your diesels with diesel fuel you get from a pump with a dated filter mounted on the pump.