Anyone know why the o ring on the fuel filter/regulator is green on the line going to the fuel check valve, and black on the line coming from the fuel pump? Yet the parts breakdown says they’re the same o ring? (P/N 11387a)?

 

The green o-ring, fuel line, and fitting looks like an aftermarket piece/assembly.

Possibly Quantum Fuel Systems..... if you look closely, the hose will often be embossed with the "Quantum" name on it.

 

Yes, that’s a new Quantum check valve fitting. But the OE Harley one was also green. IDK 🤷‍♂️

 

I don't know why a part number o-ring would have different colors...

Just a guess, but I do know that at one point (the years all start to blend together after a while) that Harley upgraded numerous o-rings from Buna rubber to Viton (better rubber).

When they did that, the color often changed. Not sure on the part numbers though.

If it's not leaking, I wouldn't worry about it....

 

Yeah that may be what’s going on. I figure that, or two other possible scenarios.
1. The parts manual is wrong and they are indeed supposed to be two different part numbers. Or,
2. The suppliers for the parts install different o rings on the assemblies when shipped. i.e. Delphi sends the pump and attached hose with a black o ring, and whoever the check valve/fuel line assembly supplier is ships them with a green one.