Section II. OPERATION UNDER UNUSUAL CONDITIONS

g. It is essential that you periodically check the

the choke. This floods the cylinders

engine oil pressure gage and ammeter during

with raw gasoline, which washes away

operation to assure that they remain within their

the lubricants and makes the engine

required ranges.

susceptible to wear.

To stop the engine, you press and hold the magneto

h. You can put the pump in standby condition

switch (5, fig. 2-1) until the engine stops. If the

by closing the discharge valves. However, extended

engine had been running hard and is hot, do not

pump operation with both valves tightly closed will

stop it abruptly. Instead, you should reduce the

cause the fluid in the volute to heat up and possibly

load by operating the throttle lever to reduce speed

boil. To avoid this you can leave one of the

and shut off the suction valves to remove the load.

discharge valves cracked open slightly to maintain

Allow the engine to run for 3 to 5 minutes before

a continuous flow of fluid through the pump. If this

shutting off. This will allow internal engine tem-

is not possible, shut off the pump to prevent long

peratures to decrease, minimizing the danger of

non-pumping intervals from causing excessive

valve warpage and other internal engine damage.

heating of the fluid being pumped.

2-5. Stopping

CAUTION

Do not stop the engine by pulling out

Section II. OPERATION UNDER UNUSUAL CONDITIONS

diminishes at higher altitudes. Make sure that the

2-6. Operation in Extreme Cold

engine is operating at peak efficiency, providing

a. You must keep the pump free of ice and snow

you with the highest possible pump output.

at all times. Cover it when not in use and, if

possible, provide some shelter from the weather.

2-9. Operation in Sandy or Dusty Areas

b. Refer to LO 5-4320-272-12 to assure that the

a. The frequency of air cleaner service must be

engine lubricant is the proper grade for the coldest

increased when you are operating the pumping

conditions likely to be encountered.

assembly under conditions of extreme sand or dust.

c. Keep the fuel tank filled when the pump is not

b. While filling the fuel tank, take care to

in use. By doing this you will prevent moisture from

prevent sand and dust from entering the fuel

condensing in the fuel system. Moisture in the fuel

system. Watch the fuel strainer bowl for ac-

system can freeze and clog lines, filters, and car-

cumulations of dirt.

buretor jets, preventing fuel from reaching the

2-10. Operation Under Rainy, or Humid

engine.

Conditions

d. Service the fuel filter frequently to remove any

a. Take care to prevent moisture from entering

moisture which may have collected in the fuel bowl.

the fuel system. You should fill the fuel tank im-

2-7. Operation in Extreme Heat

mediately after every operating period to prevent

a. You should protect the pump assembly from

moisture in the air from condensing and entering

direct rays of the sun if possible.

the fuel system. Maintain a careful check of the fuel

b. Allow adequate space for ventilation. If the

strainer bowl for collection of moisture.

pump is operated in an enclosure, you can use a fan

b. Take special care to prevent rust and

to circulate the air.

corrosion of exposed metal surfaces.

c. Keep the engine and shrouding clean to

2-11. Operation in Salt Water Areas

provide proper heat transfer to the air.

a. Because of the corrosive action of salt water,

d. Check that the lubricants used in the engine

use fresh water to wash off any salt water that

comply with LO 5-4320-272-12.

comes in contact with the equipment. This will help

e. Although you can stop fluid flow for short

you prevent the formation of rust and corrosion.

periods, you are advised not to do so in extreme

b. Take special care to prevent rust and

heat for the fluid may boil in the volute.

corrosion of exposed metal surfaces.

2-8. Operation in High Altitudes

The operating efficiency of both engine and pump

2-5