B. Replace the element in the fuel filter.
If the flow is still unsatisfactory, per-
form the next step.
C. Substitute another fuel pump that is
known to be in good condition and
again check the fuel flow. When
changing a fuel pump, clean all of the
fuel lines with compressed air and be
sure all fuel line connections are
tight. Check the fuel lines for re-
strictions due to bends or other
damage.
If the engine still does not perform satis-
factorily, one or more tuel injectors may
be
at
fault
and
may
be
checked
as
follows:
Figure 11C-79. Measuring Fuel Flow
1. Run the engine at idle speed and cut
out each injector in turn by holding the
end of Section 11A for the specified
injector follower down with a screw driv-
quantity per minute.
er. If a cylinder has been misfiring,
there will be no noticeable difference in
3. Immerse the end of the fuel hose in
the sound and operation of the engine
the fuel in the container. Air bubbles
rising to the surface of the fuel will indi-
when that particular injector has been
cut out.
cate air being drawn into the fuel system
on the suction side of the pump. If air
2. Stop the engine and remove the fuel
is present, tighten all fuel line con-
pipe between the fuel return manifold
nections between the fuel tank and the
and the injector.
fuel pump.
4. If the fuel flow is insufficient for sat-
3. Hold a finger over the injector fuel
outlet and crank the engine with the
isfactory engine performance, then:
starter. A gush of fuel while turning
the engine indicates an ample fuel
A.
Replace
the
element
in
the
fuel
supply; otherwise, the injector filters
strainer. Then start the engine and
run it at 1200 RPM to check the fuel
are clogged and the injector must be re-
moved for service.
flow. If the flow is still unsatisfac-
tory, perform the next step.
Fuel System and Governor