The easy way is to connect batteries but if that isn't an option.
You can start the engine by plumbing in a gravity feed tank to the mechanical fuel pump on the side of the engine. What I did was take a large syringe (sans needle) and stick it into the fuel line. I disconnected the line at the "T" fitting where the fuel return from the injector plumbs in. Pour some fuel in the syringe and let it drain down to the pump. It helps if someone holds everything so it doesn't make such a mess.
You may have to crack the fuel line at the injector if the high pressure side has air in it.
Once the engine is running the generator will power the pump to fill the lines and the fuel filter.
Under normal conditions there is plenty of fuel left in the line to start the engine for the next use.