Engine question

[cowboy40]

Don't have any "nut" on the fuel line on my tractor. Just a bolt going through the banjo fitting into the lift pump on one end and into the fuel filter base on the other end.

 

[TruChaos]

It sort of looks like a banjo bolt only it has a slot in the hex head for a screwdriver. The nut is tightened against the banjo fitting. It appears the bolt is used as some sort of adjustment as it can be screwed into the pump housing.

 

[bluechip]

There is a spring and a ball under there, inside the banjo bolt that act as a check valve. If you ever have one that runs for a second, then stops, and when you work the hand pump and it pumps up and gets hard, than be sure someone didn't move this to the line on the back side of the injector pump head. One of my ex employees (this was not how he achieved "ex" status) changed an injector pump and we spent two days trying to figure out why the tractor would start then die... it belongs on the end closest to the radiator