Thankfully this model Mercedes has been around for so long that it holds few surprises. I would be suspicious of the lift
pump, a couple of types were fitted. The early engines had a pump with a knurled plunger knob that needed to be unscrewed for priming and tightened down so the engine
could run. The later engines had a self returning plunger with a plastic cap and required no special technique other than pumping the plunger.......both types often leaked on that plunger as suction leaks
, no fuel drips.
I had a look inside an old Separ and thereís no obvious reason that leaving the bleed nipple loose would cause anything but air to get into the system. Did you bleed both ends of the injector pump
, there should be 2 bleed screws. Iím thinking thereís air in the system and if I was doing the hands on work
, my next move would be to get a container of clean fuel in the cockpit
then run 2 hoses down to the engine
establishing a gravity feed.
Itís very important to consider the possibility of sticky injector pump
plungers and have a way to cut off the intake air supply in case the engine tries to overspeed as a response to a stuck plunger.
Oh, the reason I have a spare Separ in a drawer is that itís very hard to get the square filter element ....but easier to just buy a Racor
Iím hoping for air in the system....Pete.