screws, hose connections, pipe plugs,
and filter screen cap.
(19) Housing Porosity Check.
(a) Fill fuel pump with clean fuel or test oil.
(b) Remove suction fitting at gear pump
and install fittings so an air pressure
hose may be attached.
(c) Air supply.hose line must be equipped
with a valve and gauge to control air
pressure at a maximum of 20 psi.
(d) Apply 20 psi air pressure; do not exceed
20 psi or damage to seals may result.
(e) Pour fuel oil over pump and examine
carefully for air bubbles, indicating
leaks. Alternately wipe pump or specific
area dry and check for wet seepage.
Do not use this check for seals.
(20) Gear Pump Test.
(a) Use a fuel pump build up with only the
parts required to drive the gear pump,
mainshaft cover assembly. If desired, a
complete fuel pump can be used if the
governor plunger and weight assist
removed and pump housing is filled with
fuel; this will prevent any possible
governor barrel. Gear pump may be
mounted directly to test stand with
(b) Install gear pump block plate, with
gasket on each side, between gear
pump and fuel pump body.
(c) Remove fuel pump damper from gear
pump and connect copper line from
orifice block to gear pump pressure tap.
(d) Connect the fuel suction line to the
suction side of the gear pump. Run a
connection to the fuel supply tank.
(e) Shut off the fuel manifold pressure
gauge to prevent damage from over
(f) The valve in the suction line and the
valve controlling the main flow orifice
are to be fully open. All other valves
must be completely closed. With the
valves in this position, fuel will be
routed through the manifold orifice.
(g) Start the pump drive and run the pump
at 400 to 450 rpm. The gear pump
must pick up at this speed without the
aid of priming. Any gear pump which
fails to pick up fuel must be rebuilt or
replaced in accordance with paragraph
Instructions for the Fuel Pump Test Stand. The
fuel pump test stand, figure 13-26, is required
for accurate testing and calibration of the feel
injection pump. Pump speeds may be varied
continuously from 475 to 4750 rpm. Correct
calibration of the fuel injection pump is one of
the most important procedures to satisfactory
(1) Test Oil. The fuel pump test stand must be
filled with clean test oil No. 99011-68 or