After operating the engine, shut it off
and remove the rocker covers. Inspect
the lube oil puddles that normally form
where the fuel connector joins the cylin-
der head and where the fuel pipes join
the fuel pipe nuts.
If there is any leakage at these con-
nections, the lube oil puddles will be
smaller or thinner than the puddles on
the connectors that are not leaking. Di-
sassemble, inspect and correct or replace
the suspected part (connector, washer,
injector or jumper line). Test and rein-
Figure 11C-78. Injector Follower
spect.
2. Use when the engine is not operating
too small for fuel to pass through but
such as during or after repairs.
m a y allow appreciable quantities of air to
enter.
Remove the rocker covers. Pour lube oil
over all fuel pipes and connectors which
Check for loose or faulty connections.
would normally be splashed with oil dur-
Also check for improper fuel line con-
ing engine operation. This will cause oil
nections such as a fuel pump suction line
connected to the short fuel return line in
puddles to form at the joining surfaces
a s mentioned above.
the fuel tank which could cause the pump
to draw air.
Block off the fuel return line and dis-
connect the fuel pump supply line at the
Presence of an air leak may be detected
secondary filter. Install a pressure
by observing the fuel filter contents af-
ter the filter is bled and the engine is
gauge in the filter adaptor, then apply
60-80 psi (413-522 kPa) fuel to the outlet
operated for 15 to 20 minutes at a fairly
high speed. No leaks is indicated if the
side of the secondary filter with the in-
lets plugged. Severe leaks will show up
filter shell is full when loosened from its
cover. If the filter shell is only partly
immediately. Minor leaks caused by
nicks or burrs on sealing surfaces will
full, an air leak is indicated.
take longer to appear. After maintaining
40-80 psi (276-553 kPa) for 20 to 30 min-
PRESSURIZE FUEL SYSTEM - CHECK
utes, a careful puddle inspection should
FOR LEAKS. Always check the fuel sys-
reveal any suspected connectors. Inspect
tem for leaks after injector or fuel pipe
and repair or replace connector as nec-
replacement and any time the fuel con-
essary. Test and reinspect.
nections under the rocker cover are sus-
pected of leaking. Failure to correct a
serious fuel leak in this area can lead to
3. Use while engine is operating at
dilution of the lube oil and bearing
4 0 0 - 6 0 0 RPM.
and/or cylinder kit damage.
Apply an outside fuel source capable of
6 0 - 8 0 psi (413-522 kPa) to the outlet side
Prime and/or purge the engine fuel sys-
of the secondary filter. Pour lube oil
tem before starting the fuel leak check.
over jumper lines and connectors so that
Prime the system by blocking or discon-
oil puddles form where lines and connec-
necting the line from the fuel pump, then
tors
meet.
Install
a
valve
and
a
apply fuel under pressure (60-80 psi or
pressure gauge in the fuel return line.
413-552 kPa) to the inlet of the second-
With the engine idling, close the valve
ary filter. If the system is to be purged
enough to raise the engine fuel pressure
of air as well, allow the fuel to flow free-
to 70 psi (483 kPa). After 10 to 20 min-
ly from the fuel return line until a solid
utes inspect the oil puddles to see if any
stream without air bubbles is observed.
have become smaller or run off complete-
ly. The undiluted oil will hang the same
Use one of the following methods to
as when the oil was poured on. Repair
check for leaks:
and retest.
1. Use when the engine has been operat-
i n g 20-30 minutes
11C-49
Fuel System and Governor
