Yanmar 4LHA-DTP, Operation Manual

Page: 410 / 670

Chapter 3 Fuel Injection Equipment
10. Jest Bench Adjustment of VE Pump
, 4LHA Seriei
* Warm-up operation: refer to the following:
1. Standard Type VE Pump
Attach the pump to the pump test bench and
connect the injection lines.
Using the thermometer (see Fig. 23) measure
the fuel oil temperature in the fuel tank. Before
starting operation, fill the pump with test oil.
a) Apply the spedfied voltage to test the
pump's magnetic valve.
Fix the control lever in the maximum-speed
position.
Operate the pump at the rated speed for
approx. 10 minutes.
b) Timer adjustment
Install the timing measuring device and
connect the pressure gauge.
Total timer stroke is determined by the
timer piston length.
The start of the timer piston stroke de-
pends on the spring tension force and the
fuel oil feed pressure; the spring tension
force is determined by the shims inside the
timer cover. Usually, at least one shim (0.6
mm) is placed on each side of the timer
spring.
Adjust the regulating valve so that the timer
advances at the specified speed.
c) Supply pressure test
During timing adjustment, the pump cham-
ber pressure must be within the specified
range.
d) Full-load fuel injection quantity adjustment
Adjust the full-load fuel injection quantity
through the full-load adjustment screw, and
by adjusting the tension lever attached to
the control sleeve.
Before adjustment, confirm that at the
measuring point speed is as specified. Set
the control lever to the maximum-speed
position by rotating the adjusting screw.
Adjust the full-load point by measuring the
fuel injection quantity and referring to the
specifications. The measuring point at all
speeds must be within the specified range.
The fuel injection quantity for each cylinder
must not exceed the specified quantity.
e) Idling adjustment
Adjust the idling fuel injection quantity us-
ing the control lever.
The fuel injection quantity for each cylinder
must not exceed the specified quantity.
f) Governing adjustment
Adjust the governing performance using
the control lever. The governing point is
reached when the full-load fuel injection
quantity begins to decrease, provided the
adjusting screw is set at a position ensuring
governor operation.
g) Measurement of overflow quantity
Measure the overflow quantity at the speci-
fied speeds using a measuring cylinder.
Compare the measurement with the
specified quantities.
h) Measurement of fuel injection quantity for
engine starting
Control the starting fuel injection quantity at
the specified speeds. Set the control lever
to the maximum-speed position to adjust
the starting stroke.
i) Control lever angle (see Fig. 24)
Adjust the control lever angles and
dimensions given below, referring to the
specifications.
a; Idling position/center position angle
P; Idling/maximum-speed position angle
y; Idling/partial load position angle
a; Distance from the end of idling stopper
to its boss portion
b; Distance from control lever idling posi-
tion to maximum-speed stopper
c; Distance from control lever partial load
position to idling stopper
3-1-53