Fuel line Bypass

[Fruitfarmer131]

I've been having some problems with a M6040, fuel bypass line. It runs from the high pressure pump, to a fitting with 2 hose nipples, just prior to reaching this fitting is a plastic check valve. The return line keeps popping off that connection. I was assuming that the bypass line runs back to the fuel tank, but now am not so sure. I was able to get a diagram eventually which shows the line continuing back to the filter/ priming apparatus, there is a T in the line and I am assuming that fuel runs back to the tank via the T or to the filter/primer housing?
I am trying to figure out how exactly to trouble shoot this. It would seem that the return line is blocked somewhere, but am at a loss as how to determine where. Any ideas?

 

[Russell King]

You can see illustrated parts lists here

Kubota Tractor Corporation - Illustrated Parts List

- K-PAD - Parts Lists - Illustrated Parts Lists - diagrams

apps.kubotausa.com

Here is one showing what I THINK you have but there are several variations of model and old/new! There are a couple of check valves and some “joint” that looks like it is a banjo bolt but no idea where that feeds fuel to.

It looks like fuel is fed back to the injection pump in one line and then goes somewhere else on the other side of the tee. I didn’t look for where it went on that side.