This Lister needs a bit of checking
AAny idea why the sump on my air-cooled Lister is filling up with diesel? TONY REPLIES... On most other engines that symptom might well be an injector, injector pump or liftpump problem, but on your type of Lister it’s most likely a fuel pipe has fractured or a fuel union come loose inside the engine case.
Take the rocker cover off and run the engine on idle. Are any of the large and small pipe union nuts on each injector dripping? If so, tighten them. Check the thin pipes have not chafed against a pushrod and punctured. If not, remove the pushrod side cover that houses the injector pumps and check no injector pump bleed screws are leaking. Make sure the main injector pumps’ unions and the banjo unions that feed fuel to the injector pumps are tight. Check the pump element retaining screw at the back of the pump (by feel or with a dentist’s mirror) for leaks.
Next, look at all the copper fuel supply and leak-off pipes inside the engine housing.
If you can still not find a fault, consider the items I mentioned at the start.