Section V. OPERATION UNDER UNUSUAL CONDITIONS

Make sure that some passage of liquid continues

a. Start the centrifugal pump (para 2-8).

through the pump during operation.

b. Open the suction gage valve (7, fig. 2-3) and

g. If the rate drops off for no apparent reason,

discharge pressure gage valve (8) to operate the gages.

check the suction line for blockage or closed valves.

Open the air eliminator valve (1) if necessary to

eliminate air from discharge system.

h. If the engine stops due to an engine overspeed

condition, correct the cause of the overspeed and press

c. Pull the throttle knob (5, fig. 2-2) all the way out

the reset button (2, fig. 4-2) on the top of the engine

and operate the pump at maximum governed speed.

overspeed governor to reset the overspeed circuit

Depending on pumping conditions, the pump may not

before attempting to restart the engine.

start pumping immediately, since it is necessary for the

suction hose to fill with water. If after a reasonable time

i. If the engine stops due to a low oil pressure

the pump fails to pump, check the suction line carefully

condition, press the low oil pressure reset (15, fig. 2-2)

for leaks. A small air leak will greatly reduce pumping

to reset the oil pressure circuit before attempting to

efficiency under any conditions and especially when

restart.

operating under a high suction lift.

j. Stop the pump as directed in paragraph 2-9

d. After the pump starts pumping, as indicated by

when the pumping cycle is completed.

a reading on the discharge pressure gage, close the air

Warning

eliminator valve and adjust the flow from the air

When filling the fuel tank always

eliminator valve and/or a throttle control on the control

maintain metal to metal contact

panel to obtain the desired pumping rate or discharge

between the filling apparatus and

pressure.

fuel tank to prevent a spark from

e. Check the pump for any unusual or excessive

being caused by static electricity.

vibration. If excessive vibration is noticed, stop the

k. During operation, check the fuel level gage (2,

pump immediately and correct the cause. Vibration

fig. 2-4) at intervals and, when necessary, remove the

usually results when the pump or connecting lines are

filler cap (3) and add 91A Gasoline to fill the tank.

not properly supported, alined or secured.

l. Check the air cleaner restriction indicator at

f. While the pump is in operation, do not

intervals during operation. If the restriction indicator

completely close the valve in the discharge line.

shows red, it indicates that the air cleaner requires

Although no serious harm can be done to the pump, the

servicing after shutdown.

rotating impeller churning the water can generate

enough heat to cause the liquid in the volute to boil.

Section V. OPERATION UNDER UNUSUAL CONDITIONS

2-11. Operation in Extreme Cold

e. Service the fuel filter frequently to remove any

moisture which may have collected in the fuel bowl.

a. Keep the pump free of ice and snow at all times.

Cover it when not in use and, if possible, provide some

2-12. Operation in Extreme Heat

shelter from the weather.

a. Protect the pump assembly from direct rays of

b. Use a hydrometer to assure that the engine

the sun if possible.

coolant has sufficient antifreeze to prevent freezing at

b. Allow adequate space for ventilation. Use a fan

the lowest temperature to which the pump will be

to circulate the air if the pump is operated in an

subjected.

enclosure.

c. Refer to the current lubrication order to assure

c. Keep the engine and radiator clean to provide

that the engine lubricant is the proper grade for the

proper heat transfer to the air.

coldest conditions likely to be encountered.

d. Check that the lubricants used in the engine

d. Keep the fuel tank filled when the pump is not in

comply with the recommendations of the current

use. This will prevent moisture from condensing in the

lubrication order.

fuel system. Moisture in the fuel system can freeze and

2-13. Operation in High Altitudes

clog lines, filters, and carburetor jets, preventing fuel

The operating efficiency of both engines and

from reaching the engine.

pumps diminishes at higher altitudes. Make sure

2-8