how to bleed fuel system

   / how to bleed fuel system #1  

davewine

New member
Joined
May 16, 2012
Messages
1
Location
walla walla wa
Tractor
john deere 750
I have a john deere 750 and can't bleed fuel system after it ran out of fuel. any help please. Will bleed at filter but not at bleeder screw on pump no mater how long I turn it over.
 
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   / how to bleed fuel system #2  
I have a john deere 750 and can't bleed fuel system after it ran out of fuel. any help please.

im not exactly sure about the 750, but my JD 870 had a manual bleed lever on the side of the injector pump that you could move with your finger to prime the pump.

On other systems, you have to crack the injector lines at the separate injector heads and cycle the tractor to pump out the air.
 
   / how to bleed fuel system #3  
I have a john deere 750 and can't bleed fuel system after it ran out of fuel. any help please. Will bleed at filter but not at bleeder screw on pump no mater how long I turn it over.

Have you tried removing the fuel line at the pump to see if the problem is in the fuel line or in the pump?
 
   / how to bleed fuel system #5  
I have a john deere 750 and can't bleed fuel system after it ran out of fuel. any help please. Will bleed at filter but not at bleeder screw on pump no mater how long I turn it over.


Here's a general method for bleeding a diesel fuel system


Bleeding a Diesel Fuel System
Start at the fuel outlet of the tank (inlet to the filter). Shut the tank valve, remove the line at the filter inlet and holding a suitable container to catch the diesel fuel, open the valve. You should have a CONTINUOUS rush/flow of fuel out of the line. If it dribbles or is intermittent, check the fuel cap for a blockage of the fuel vent or the strainer upstream of the valve for clogging. The strainer/screen is attached to the shut-off valve, and is positioned up inside the tank. You will have to drain the tank and pull the valve to clean the screen.
If you have good fuel flow at that point, reconnect the line and open the bleeder screw at the top of the filter. Turn on the tank valve and wait till you have a steady flow of fuel with no bubbles at the top of the filter, then close the bleeder screw.
Your pump may have a bleeder screw. If so, open that until fuel streams out with no bubbles, then close it. If you cannot identify the bleeder screw, loosen the inlet connection at the pump and purge air at that point.
Go back and make sure ALL the fittings in the fuel delivery system are tight so they cannot suck air.
Make sure the battery is fully charged. Loosen the fuel fittings at the injectors, either one at a time or all at once. Crank the engine till you see all fuel at the injector fittings and then tighten the fittings. If you do indvidual fittings, the engine will usually start before you get to the last fitting.
Alternatively, you can "tow-start" it to save wear and tear on your starter. Leave the injector lines cracked open at the injectors at first to purge the lines. Then tighten them up and she should start.
Your injection pump puts out a very small amount of fuel (high pressure/low volume). BE PATIENT. If the lines are totally empty, it takes a lot of cranking to fill them up.


sixbales & Jerry/MT
 
 
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