Fuel Density Compensator (Code F Injection Pump)

TM 9-2910-226-34

diametrically from the fuel pump end of the hub and

1-18. Fuel Density Compensator (Code B, C, D and

is channeled to receive the ends of the three timing

E Injection Pumps).

device springs (B). The new style hubs do not have a

NOTE

flange and are counterbored to receive the timing

The key letters shown below in parentheses

device springs. The springs oppose the flyweight

refer to figure 1-16.

forces of the weight and spider assembly (AH).

a. The density compensator housing (BB), and

c. The weight and spider assembly has external

gasket (Y) are attached to the top of the governor

right hand helical splines to mesh with the internal

housing.

helical splines of the sliding gear. The splined end is

b. The compensator housing cover (EE) and

housing cover gasket (FF) enclose the servo spring

machined to receive the end play spacer (AE). Three

(GG) and the servo pressure well.

flyweights are pinned to a flange adjacent to the

splines. The weight and spider thrust plate (AG),

c. The pressure regulating valve (JJ) is adjusted

by the use of shims. This valve determines the servo

located between the flange and the timing device

system inlet fuel pressure.

housing, carries the back-thrust of the flyweights

d. The fuel outlet is through an elbow at the right

and prevents housing wear,

front of the housing connected by a tube to the fuel

d. The sliding gear has internal left hand helical

injection pump overflow valve tee.

splines at one end and internal right hand helical

e. The servo pressure valve (CC) is adjusted

splines at the other end and meshes with the external

during calibration of the density compensator to

splines of both the weight and spider assembly and

provide the correct fuel pressure on the piston (H H )

the timing device hub. Correct assembly of the spline

and establish the travel of the stop plate (PP).

train is insured by a wide land on both the hub and

f. The stop plate guide (AA) provides adjustment

weight and spider assembly. The sliding gear has a

of the fulcrum lever in the injection pump.

missing tooth on each set of internal splines to

g. The guide bears against the stop plate (PP)

receive the wide lands. Three arms extend from the

which, in turn, contacts the smoke limit cam (MM).

outer surface of the sliding gear and provide seats for

The guide can be adjusted to move the stop plate

the three timing device springs. The force on the

laterally, thereby regulating the travel of the

springs is controlled by a sliding gear spacer (AF).

governor fulcrum lever (NN).

1-17. Fuel Density Compensator (Code F Injection

1-19. Fuel Density Compensator (Code A Injection

Pump).

NOTE

The key letters shown below in parentheses

refer to figure 1-15.

refer to figure 1-17.

a. The diaphragm housing (BB) is attached to the

a. The density compensator housing (BB) and

top of the governor housing and contains the stop

gasket (Y) are attached to the top of the governor

plate (PP), guide (AA), inlet housing diaphragm

housing.

(LL), and related parts.

b. The compensator housing cover (EE) and

b. The fuel inlet housing (DD) attaches to the

housing cover gasket (FF) enclose the servo spring

diaphragm housing and contains the fuel inlet port

(GG) and the servo pressure well.

(JJ) and pressure regulator valve (HH).

c. The pressure regulating valve (JJ) is adjusted

c. The pressure regulator valve (HH) is adjusted

by the use of shims under the plug at the spring end

by the use of shims. This valve determines the inlet

of the valve. The valve determines the servo system

fuel pressure.

inlet fuel pressure.

d. The fuel outlet housing (EE) attaches to the

d. The fuel outlet is through an elbow at the right

fuel inlet housing and contains a fuel outlet port

front of the housing connected by a tube to the fuel

(GG) and an adjustable servo pressure valve (FF).

injection pump overflow valve tee.

The fuel outlet housing also has a recess for the servo

e. The servo pressure valve (CC) is adjusted

spring (CC ).

during calibration of the density compensator to

e. The servo pressure valve (FF) is adjusted

provide the correct fuel pressure on the piston (HH)

during calibration of the density compensator to

and establish the travel of the stop plate (PP).

provide the correct fuel pressure drop across the inlet

f. The stop plate guide (AA) provides adjustment

housing diaphragm (LL), establishing the stop plate

of - the fulcrum- lever in the injection pump.

(PP) travel.

g. The guide bears against the sliding stop weight

f. The stop plate guide (AA) provides adjustment

(AK) and stop plate (PP) which, in turn, contacts

of the fulcrum lever in the injection pump.

the smoke limit cam (MM). The guide can be ad-

g. The guide bears against the stop plate (PP)

justed to move the stop plate laterally, thereby

which, in turn, contacts the smoke limit cam (MM).

regulating the travel of the governor fulcrum lever

The guide can be adjusted to move the stop plate

(NN).

laterally, thereby regulating travel of the governor

fulcrum lever (NN).

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