case 580c no fuel to injectors

I have a case 580c that worked great last fall and will not start now. To be sure fuel is getting to stanadyne injection pump, I put a 1 1/2" x 12" long pvc tube on the inlet to the fuel injection pump (before filter screen). Filled with 1 + cup (10 oz) of clean diesel and started cranking. Cranked for 5-10 sec intervals over two hour time period so I didnt burn up starter. Fuel injection lines to #1 &#3 cyls. were open but no fluid was pumped out. No fluid is in return lines or in upper pump body (checked by removing return line fitting with glass ball). Any ideas?