fuel problem with JCB 456?

I am currently in Afghanistan and am having issues with our JCB 456 HT, I believe it is the low quality of fuel we recieve here. The machine idles fine and will operate under a light load fine but when put under a heavy load it cuts out and eventually dies. I have tried draining the filters and water fuel seperators but this is a rel pain since i can not locate a mechanical primner to re-prime the system. if anyone has any suggestions I would greatly appreciate it.