Engine not idling right

[Jezza_hr]

When pulling the plugs they are pretty well carbonised, I cleaned them up and put them back in again. When I took them out a second time they were heavily carbonised again, much as you would expect from a pretty rich running engine.

The return you're explaining does sound like a possibility. The leak was on the inlet line though and not the return line. But if the fuel pressure is too high due to a blockage in the return line then I guess that could have still caused the inlet line to leak. I did pull off and look over the return line and there didn't appear to be any kinks. I did try blowing into it (with the fuel cap off), which seemed hard work, but I don't know how much pressure there should be in there for reference.

Annoyingly I don't have a fuel pressure tester to check what PSI I'm running, I may need to see if I can borrow one, since they're about £30 new from what I can see.