Operation. - TM-5-4320-273-140026

TM 5-4320-273-14

Inspect for any

time, or if the unit has been standing idle for a con-

a. Unusual Operation and Noises.

unusual operation, such as engine overheating or

siderable length of time. Using the hand primer lever

running at below-governed speed or failure of the

(1, fig. 2-2), fill the fuel lines and the carburetor float

pump to deliver desired volume or to respond to con-

bowl and the strainer bowl. When priming, a distinct

trols. Stop operation immediately if any unusual

resistance to movement of the hand primer should be

noise is noticed.

felt, If you do not feel this resistance, turn the engine

b . G a g e R e a d i n g s . Check all gage readings

crankshaft one revolution so that the fuel pump lobe

frequently; watch particularly to see that there is no

on the camshaft is rotated out of engagement with

unusual drop in engine oil pressure and that the am-

the fuel pump cam follower to permit movement of

meter is operating within its normal range.

the fuel pump diaphragm with the lever. Assuming

c. Leaks. Inspect the entire unit for leaks, paying

the gasoline strainer is empty, about 26 strokes of the

particular attention to the suction hose fittings.

primer lever are required to fill the bowl. After the

strainer bowl is full, an additional 5 to 10 strokes are

2-7. Stopping.

required to fill the carburetor bowl. When this bowl

a. Reduce the engine speed by means of the throt-

is full, the primer lever will operate with less

tle lever and remove the load by shutting off the suc-

resistance.

tion valves, Allow the engine to idle from 3 to 5

d. Pull out the throttle control (2, fig. 2-1) halfway

minutes to cool evenly and prevent warping of the

and place the ignition switch (6) in ON position.

valves.

b. Press and hold the ignition switch in the OFF

e. Pull out the choke control (1) all the way.

position until the engine stops,

f. Pull out the oil pressure safety switch plunger (7)

about 1/16 inch and engage the spring clip into the

2-8. Temporary Stop Services.

recessed underside of the housing to hold the switch

When the unit is stopped, even for short periods, you

contacts open for starting. You must reset this switch

should make a general inspection of the equipment.

each time you start the pump.

If time permits, minor deficiencies should be correct-

ed during temporary stops.

g. Depress the starter switch (5). After several

revolutions of the crankshaft, push in the choke con-

2-9. After Operation Services.

trol (1) half way. If the engine should fail to start af-

To ensure that the equipment is ready to operate

ter a few revolutions of the crankshaft, do not con-

at any time, the daily services indicated on the

tinue to crank with the starter. Use short, in-

preventive maintenance services check-list (table 3-1)

termittent starting cycles to prevent overheating of,

must be performed by the operator or crew im-

and possible damage to, the starting motor.

mediately after every operating period.

h. After the engine starts, adjust the choke so that

2-10. Breaking in a New Engine.

the engine runs smoothly. Run the engine for a few

Careful breaking in of a new engine will greatly in-

minutes to allow it to warm up and then push the

crease its life and result in trouble-free operation.

choke in all the way.

After inspecting and servicing the unit, follow the

2-5. Operation.

starting procedures and, if possible, proceed as

a. To start product flow, open the suction and

follows:

discharge valves and adjust the engine throttle (2,

a. Operate for one-half hour at 1,000 to 1,200

fig, 2-1) so that the tachometer indicates no less than

revolutions per minute without load.

1400 revolutions per minute. Fluid flow should be in-

b. Increase to engine operating speed for an ad-

dicated by the movement of the check valve override

ditional 2 hours without load.

handle as the check valve is pushed open.

c. If possible, operate at light loads for about 8

hours before maximum load is applied.

b. Open the discharge valves and increase the

engine speed to achieve the desired flow rate,

2-11. Performance Curve.

A composite pump performance curve (fig. 24) for

2-6. During Operation Services.

You must remain alert in order to correct or report

this pumping assembly is located under the tool box

any deficiency in performance or other signs of

cover. It indicates the pump capacities in relation to

unusual operation.

revolutions per minute and dynamic head

2-4