C4, TM 9-2350-230-12
9-9. Engine Fuel System (Fig. 9-17)
a. Checking Fuel Flow.
(1) Insert end of a wire through one of the pump
body drain holes, then crank engine momentarily
(1) Open exhaust grille doors, disconnect fuel return
and see if wire vibrates. Vibration will be felt if
hose at quick disconnect (Fig. 9-4), remove
pump shaft rotates.
disconnect from hose and place end of hose in a
(2) Without removing pump from engine, unscrew
one gallon container.
valve plug; and remove gasket, spring, pin, and
(2) Start and run engine at 1200 rpm and measure
valve. Wash parts with solvent and blow out
the fuel flow return for a period of one minute.
valve cavity with compressed air. Install valve
Approximately one-half gallon of fuel should flow
parts and check flow.
from the return hose per minute.
9-10. Engine Coolant System (Fig. 9-28)
(3) Immerse end of fuel hose into fuel container. Air
bubbles rising to the surface of the liquid will
a. When coolant system has been drained to service
indicate a leak on the suction side of the pump.
coolant components, the system should be flushed to
Check all hose connections and gaskets on
remove scale deposited by hard, mineral-laden water.
strainer and filter elements.
(1)
Drain system (table 5-4).
(4) If the fuel flow is insufficient for satisfactory
engine performance, then check the strainer
(2) Refill system with clean soft water. If engine is
element and filter element and replace either or
hot, fill slowly to prevent distortion of engine
both if clogged. Start engine and run it at 1200
castings.
rpm to check fuel flow. If fuel flow is still
unsatisfactory, replace fuel pump (fig. 9-19) and
(3) Start engine and operate for 15 minutes.
again check flow. When changing a fuel pump,
clean pump lines with compressed air and be
(4) Drain coolant system completely (table 5-4).
sure all fuel line connections are tight.
(5)
Refill cooling system according to Table 9-2.1.
(5) Connect fuel return hose to quick disconnect.
b. Whenever hose connections have been disturbed or
b. Checking Fuel Pump. If the fuel pump fails to
when coolant system has been drained, retorque clamps
function properly, check for broken pump shaft or dirt in
to 40-60 pounds-inches after engine has been operated
relief valve before removing the pump from the engine:
to normal operating temperature.
TABLE 9-2.1. COOLANT MIXTURE
AMBIENT
TEMPERATURE
ANTIFREEZE
INHIBITOR
-65F to -40F
6850-174-1806
--------
Full strength
6850-243-1992
--------
-40F to+80F
or
--------
50-50
6850-224-8730
--------
Above 80F
--------
6850-753-4967
22-1/2 oz.
9-14
