pressure on the fuel within the pumping chamber.
Residual pressure in the fuel lines closes the reverse
flow check valve in the pump and prevents surges on the
fuel lines. No fuel flowing permits the injection valve to
close and complete injection.
The camshaft continues to lift the plunger to the top
of the stroke. The fuel in the housing fills the space in
the pumping chamber through the fuel outlet until the
sleeve closes the outlet on the downward stroke. Spring
pressure pushes the plunger farther down as the
Figure 5-15.-Sleeve metering fuel pump.
camshaft rotates, allowing the fuel inlet to fill the rest of
the chamber and restarting the cycle.
GOVERNOR. The mechanical type governor
shaft of the governor for the sleeve metering fuel
system controls the position of the sleeve on the
plunger, which regulates the amount of fuel injected.
The volume of fuel injected is equal to the
displacement of the plunger lift into the barrel
between the start and end of injection. The start-up
control sets the fuel injection pumps at full stroke to
aid in starting, regardless of the throttle position.
Normal governor operation takes over at low-idle
speed, approximately 500 rpm.
TROUBLESHOOTING AND ADJUST-
MENTS. Most problems in this system can be traced
to lack of fuel, low fuel pressure, dirty fuel filters, poor
quality fuel, or a broken or damaged fuel line. Air enters
the fuel system when there are loose connections of the
suction side of the pump.
Individual fuel injection pumps for each cylinder
with built-in calibration means little or no balancing or
adjustment. Before you calibrate any sleeve metering
fuel system, be sure the proper tools and manuals are
ROOSA MASTER FUEL
The Construction Mechanic 3 & 2 covers the
general construction and operation of the Roosa Master
DB and DC fuel injection pumps.
In this TRAM AN, you will learn about
troubleshooting, disassembly, inspection, reassembly,
and testing of the basic DC fuel pump of the Roosa
Master system. Before you perform any work on an
injection pump, refer to the manufacturers maintenance
and service manuals.
The troubleshooting chart (table 5-1 ) lists some of
the problems and their possible causes that you might
encounter in the Roosa Master fuel system.
A field test (Kiene) on an engine is an efficient way
to pinpoint the cause of poor engine performance. This
test will eliminate unnecessary fuel injection pump
removal. Since this field test permits some analysis of
engine condition, as well as the fuel system, you will
quickly see the extent of the difficulty and the required