Ford F-650 Owner's Manual page 209

Cleaner air - gasoline engines
Ford endorses the use of reformulated "cleaner-burning" gasolines to
improve air quality, per the recommendations in the Choosing the right
fuel section.
Running out of fuel - diesel engines
Avoid running out of fuel as this allows air to enter the fuel system,
which makes restarting the vehicle difficult.
If you have run out of fuel:
• If your vehicle is equipped with dual fuel tanks, add at least
4–5 gallons (15–19 liters) of fuel to each tank before attempting to
restart the engine.
• The fuel system must be primed before attempting to restart the
engine. Refer to the engine operator's manual for instructions on
priming the engine.
• Use caution not to overheat and damage the starter by cranking
the engine for an excessive period of time. You may need to crank the
engine for a longer time than normal. If the engine fails to start in
30 seconds, turn the ignition to the off position and wait for two
minutes before cranking the engine again.
• Any remaining trapped air self-purges from the fuel system once the
engine starts running.
• The engine may run rough and produce white smoke while air is in
the fuel system. This is normal and should stop after a short period of
time.
Running out of fuel - gasoline engines
Avoid running out of fuel because this situation may have an adverse
effect on powertrain components.
If you have run out of fuel:
• You may need to cycle the ignition from off to on several times after
refueling to allow the fuel system to pump the fuel from the tank to
the engine. On restarting, cranking time will take a few seconds longer
than normal.
• If your vehicle is equipped with dual fuel tanks, adding
4–5 gallons (15–19 liters) of fuel is enough to restart the engine. If the
vehicle is out of fuel and on a steep grade, more than 4–5 gallons
(15–19 liters) may be required.
2012 F-650/750 (f67)
Supplement, 2nd Printing
USA (fus)
Maintenance and Specifications
209