Farmtrac 535 Air in injector pump

[Tex5String]

After draining a little water from the fuel filters, I had to remove the fuel filter bracket to replace a broken air bleed screw. After bleeding the air from the fuel system per the owner's manual, the tractor wouldn't fire. I loosened the high-pressure fuel line nuts at the injectors, cranked the engine to pump out any remaining air bubbles, then tightened one nut gradually while cranking(I have very long arms!). That cylinder started to fire, so I released the key and tightened the other two nuts, bringing the other two cylinders on line. I was able to use the tractor for about a half-hour, then it started to lose power. I parked it. I had to go through the same high-pressure air bleed while cranking the next two times I used the tractor. Evidently there is air somewhere in the fuel path, and it sends a few bubbles on their way after a half-hour of operation. The tank is half full, the fuel shutoff valve is wide open. The pump is a Bosch unit, according to the trademark stamped into it. Any suggestions? Much appreciated!

 

[firedog]

Sounds like you might be sucking some air in one of the lines or at the sediment bowl. Check all fittings.

 

[Tex5String]

Checked at the dealer's today and a mechanic told me to drain the tank and clean the sediment screen above the tank shutoff valve -- dirt in the diesel sold around here tends to clog the the screen after a half-hour of running. Then when the engine shuts down, the crud falls off the sides of the screen and it is ready to start and run again for 30 minutes. I'll try that tomorrow. Looks like you got it right, firedog -- Thanks!

 

[Tex5String]

So when I got the tanker filter screen out, it was covered with a thick layer of a dark-brown crud the consistency of peanut butter. I cleaned it off, washed the screen with white gas and blew it out with compressed air. Next weekend I'll get time to refill the tank and fire it up.