Cm2250 Won't prime/no fuel in water separator

[JimT]

which filter are you using in the davco? I've had similar issues with my davco unit, old and a new one, where the fuel level would drop below the clear housing. Never did find an actual, definitive cause, but so far since I switched to the smaller filter I haven't had any issues. I have to look up which number it is, there's actually 4 that are compatible with that housing, 2 larger and 2 smaller.

Also, you need to double check that the o-rings are installed correctly. Check ALL the fuel lines going into/out of the main fuel filter.

Maybe try Biobor JF for a fuel treatment. There are a few causes, including 2 different groups of biologicals that respond differently to different products. I use the Biobor in the first tank of fuel after a davco filter change. If it does the job you will know very fast as the dead junk collects in the filter resulting in another filter change.

It could also just be soot collecting in the fuel. After my inframe my davco filters no longer turn black and the current one has over 30,000 miles and is only half way up the filter - and it's the smaller filter too.