There is an 1 1/4 hose in the passenger frame rail just under 2 feet long. Replace it and the clamps. All of them seem to leak after awhile.
There was a dude yesterday with a 565 with just under 200K on it getting his fuel water separator changed, and it was black. Not kinda of black, black. I thought I read on here what caused that or it was algae contamination. It's a canister type filter. If you didn't know it was a FWS you'd look at it and swear it was an oil filter.
Sounds like someone got a lot of bad fuel. I heard about a lot of guys with the paccar fws having problems with it clogging but the davco one works fine...but that’s an unrelated issue.
What happened to the original X - 15 ? I love cummins motors but the answer to your question is the 12.7