I would get several feet of 5/16" Fuel Hose from the regular Parts Store; enought to go into a seperate Container of 2 or mor gallons of clean Diesel Fuel.
And, do what moon161 said concerning priming the system. If Fuel does not come out of the Fuel Fuel Injection Lines like that try cranking the Engine while some one works the Hand Primer. If that works the Fuel Supply Lift Pump could have issues or the Fuel Pressure/Overflow Valve is not holding pressure.
If no Fuel is coming out of the Injector Lines like that I would look up some of the Threads were the Car sat a long time and it was believed the IP was plugged up internally.
2 things can happen; the Fuel Feed Holes in the Elements can be plugged and or the Plungers can get stuck upwards due to old sticky Fuel.
Here is one thread:
See post #4 Reasons for stuck Rack or other similar symptoms of no fuel from IP
81 617 alda clogged after i cleaned it two days ago
DIY Repair Links
DIY Links by Parts Category - PeachParts Mercedes ShopForum
PeachPartsWiki: Do It Yourself Articles - Mercedes Vehicles
People have used various chemicals to unstick things.
Once you get Fuel out of the Fuel Injection lines it is also possible the Injectors are gummed up.