3 days and no takers on this one? gee whizz...
ok PIPELINE_Welder i'll take a stab at it.
Generally if these Deutz engines won't run or has any issues running it has to do with something in the fuel system. Clogged fuel filter, pinched fuel supply line between the tank and the engine or possibly a bad fuel pump. It sounds like the pump may be weak to me and it just can't keep the fuel pressure up, it's just not pulling it from the tank well enough. Being a 2006 i'd say the diaphragm in the pump might be hard or cracked.
Try replacing the filter, if that doesn't help then put a fuel pump on it (if you don't find any issues with the supply line. (also there is a shut off valve on the fuel tank where the supply line comes out, make sure it is open all the way).