I have a recently bought 5211 I've used about 10 hours. It seems to run out of fuel unless the tank is near full. I suspected a clogged fuel filter, so I changed it. The old one was quite clean. The owner's manual was not much help on how to purge the air. I found a bleed screw on a banjo bolt going into the injector pump, so I opened it up and used the manual pump until I got only fuel coming out. Everything seemed OK, but the tractor wouldn't start. I got it started on starter fluid, but it would not continue running. So I ran it on starter fluid for about ten minutes, a little spurt at a time, hoping it would purge its self. No luck. Can someone tell me how to purge the fuel system? What is likely to be my "running out of fuel" problem? Bad lift pump?