Russ Calasant
Active Member
The black crud on the bottom of your Racor bowls is probably asphaltenes that precipitate out of diesel fuel. Apparently, ULSD made asphaltene issues worse. Do a google on "aspahltenes in diesel fuel" and you can find more information. I have petcocks on the bottom of my racors and drain out the black crap from the bottom about twice a year from them (about a shot glass worth). There is really not much you can do about this stuff precipitating. I took the bowls off the Racors and few years ago and cleaned them out really good before I put the drain petcocks on.
Thanks Gary, very helpful. Was it a big deal to remove the bowls? I see 4 bolts, is there a gasket?