S77 Diesel.  My tractor died while idling.  I had just finished replacing the connector on the driveshaft to the clutch a few days ago. I had the fuel tank off to do the repair and when I replaced it I checked the level as I knew it was almost empty. I forgot  and failed to add any fuel and when it died I just assumed it was out of fuel. stupid&quot;&quot;&quot;&quot; I knew it is difficult to restart the system.  I checked the owners manual and they explained how to bleed the injector lines to get the air out of the lines. I loosened the coupler on each of the injectors and figured the pressure from the pump would purge the air out. I have a electric fuel pump on the tractor so I just ran it a while and assumed the air problem was gone. I drained the sump of water and added 5 gal. of  fuel. Would not start. I checked to see if the electric pump was working, plenty of flow. Thinking the worst  as no fuel came out of the injector lines I began to suspect the injector pump was not pumping. I accidently noticed the shut off lever on the injector pump was loose. The spring had broken while the engine was idling and shut off the fuel flow.  The old spring was hanging from the throttle rod and not noticeable.  I wasn't out of fuel, the broken spring had shut off the tractor when it broke.  Even a blind squirrel gets an acorn once in a while.