This machine had a leak in the fuel line. I replaced the fuel line with a clear hose. The machine would not start after this. It starts if I squirt diesel in the intake then dies after about 10 seconds. I added 6 gallons of fuel to the tank to be sure it was not out of fuel. When I pump the hand pump, I can see the fuel going back and forth in the clear hose. Is it supposed to go back and forth? I open the bleeder on the fuel filters and no fuel comes out..not even while pumping the hand pump. I took the fuel line off at the hand pump and put my thumb over it and I can feel it push on my thumb when I press down and I can feel it suck on my thumb when I release. Is my hand pump bad? I would think there was supposed to be some kind of a check valve in there that kept the fuel from just going back and forth.
Yep, sounds like one of the check valves isn't working. You could try using your finger as the check valve, releasing the air then holding your finger tight so the pump doesn't suck the air back. That should show you that it will pump with a "digital" check valve. Or try blowing some air through the pump in the direction it pumps, or using a couple of PSI on the tank in order to prime the system, and see if the pump clears itself of any gunk that might have gotten into the pump. Not a bad idea to check if there's a restriction on the tank side of the pump also.
The check valve in the fuel line has a problem. It will most likely need to be replaced. It is #9 in the drawing. Also be aware that there is a fuel strainer in the tank. It is #1.