I have a rebuilt 1555 diesel. Pump was gone through by professional that is now retired about 8 years ago. It would ocassionally die from fuel starvation. Found a plastic gas jug cap floating in tank that I assumed got pulled down on Strainer assembly. Thought problem was fixed. After sitting awhile it did not start. Tried everything plus new filters. Finally pulled pump and had it checked. Tested good. Put together twice because I rolled a pump seal on the first attemp and had fuel in oil. Ran good for a long time with little use. Thought I ran it out of fuel today. Added fuel and started up only to quit again. Would not prime so I blew air through strainer. Bled lines and ran good then died. Replaced fuel strainer after letting a lot of fuel run out. Bled lines and started right up only to die again. Checked the little fitting off the pump for fuel return. It was clean. Tightened all fittings worried about an air leak. Still dies. Is there something in the pump that can be shutting this tractor down. Do you think I need to put in more than 3 gallons of fuel? I am about to lose my patience. Thanks for any advice.