As for your other fuel leak, you need to check the injection pump units. On those engines each injector has a pump unit. Remove the metal cover just above the filters, two 13mm hex head screws, see if you have wet fuel on one or more injector pump units. Common problem on those engines, where the injection line connects to the pump unit, that fitting of the injection pump unit has an o-ring that seals it where it screws into the injection unit housing, very common for that o-ring to age and leak. It's an easy fix to replace that o-ring if that's what you have leaking. As for the harness wires getting brittle, yes, that's a common problem as well, gets brittle to the point of insulation falling off the wire leaving bare wires, you may notice that as well when you pull that cover off.