ARMY TM 9-2815-256-24
AIR FORCE TO 38G1-96-2
MARINE CORPS TM 2815-24/5
Remove inlet and outlet fittings.
Install vacuum/pressure gage to inlet side of pump.
Move primer lever all the way upward. Release lever and at same time observe gage.
Gage needle should move to some value, and then very slowly go back to zero (0). This indicates inlet
valve and diaphragm are in good condition. Proceed to step d.
If gage needle does not move at all, or needle moves rapidly to zero (0), pump is defective and must be
Remove vacuum/pressure gage and install onto outlet side of pump.
Move priming lever all the way to upward position. Release lever and at same time observe gage.
Gage needle should initially read 4 to 6 psi (28 to 41 kPa), then return to zero (0) very slowly. This indicates
outlet valve and diaphragm are in good condition. Fuel supply pump is operating properly.
If needle reaches some value on gage and then falls immediately back to zero (0), pump is defective and
must be replaced.
3-25.2.2. Leakage Test.
Leakage test should be performed on a fuel supply pump suspected of leaking fuel externally or
internally, into engine crankcase.
Install an air line on inlet side of pump and apply 20 psi (140 kPa) pressure.
Hold finger over outlet side of pump or install a plug. Submerge pump into a container of water.
If air bubbles (indicating leakage) occur around banded connection holding two halves of pump together,
replace pump if leakage is observed.
If diaphragm is bad, there will be leakage through vent holes and around the rocker arm. Replace pump if
Always use two wrenches when removing/installing fittings and/or fuel lines to avoid damage.
Use teflon tape on elbow threads before installing fittings.
Install elbow (24, FIGURE 3-58) in fuel supply pump outlet.
Position new gasket (19) and fuel supply pump (22) on engine block and secure with two capscrews (20) and
Remove caps and connect fuel line to fuel supply pump inlet.
Remove caps and connect fuel line (9) to elbow (24) in fuel supply pump outlet.
Bleed fuel system, refer to paragraph 3-23.