Mooney M20B - General Fuel System Description; Fuel System Troubleshooting

SECTION
V1I
FUEL
SYSTEM
A.
GENERAL
The
fuel
system
consists
of
24
gallon
fuel
cells located
in
the
front
portion
of
each
wing.
These
cells
are
formed
by
sealing
off,
through
the
use
of
a
special
sealing
compound,
a
portion
of the
wing.
AZuminum~fuel
lines
~feed the fuel
from the
cells to
the two
way,
positive
setting
selector
valve
on
the floor
beneath
the
pilot’s
seat.
It
is
then
routed
through
the
Bendix
electric fuel
pump
to the
gascolator,or
c~diment
bowl,
by
aluminum
lines.
From the
gascolator,
it
passes
through
the
to
the
engine-driven
fuel
pump,
and from there
to
the
carburetor.
There
are
three
flush-type
quick
drains
loc~ted
ir
the
fuel
sS-stem.one
at
the
lowest
point
of
each
f~iel
cell,
and
one,
beneath
the
fuel
selector
valve.
A
c~rain
cup
is
provi;2ed
with
each
airplane
for
testing
for
water
or
sediment after
each
refueling
or
prior
to
each
flight.
B.
TROUBLESH30TING
Troubles
peculiar
to
the M
O
O
N
E
Y
~M
2
O
B
fuel
system
are
listed
in
Figure
22
along
with
their
probable
causes
and
suggested
remedies.
When
troubleshooting,
checl
from the
power
supply
to
the
items
affected.
If
no
trotitire
is
found’uy
this
method,
the
trouble
probably
exists
inside
individual
pieces
of
equipment;
they
may
then
be
removed
from
the aircraft
and
an
identical
unit,
tested
and
known
to
be
in
good
con-
di~ion
installed
in
its
place.
Table 3
F[TEL
SYSTEM TROUBLES1HOOTIM~
mEOUBLE
CAUSE REMEDY
Fuel
gage
not
indicating.
Broken
Wire
_~I
.~Ch´•eck
and
repair
Transmitting
unit
faulty
Replace
Float
hung
in fuel
cell
Check and
repair.
Circuit
breaker
out
Check and
reset
Fuel
gage
indicates
full
Incomplete
ground
Checir
gsound
connections
at
fuel
when tanks
are
not
full
transmitter
in
tank
No
Fuel Pressure Indica-
~o
fuel
in tanks Check and fill
tanks
tion
I
Check
pump
for
prop~
fuel
pressure
buildup
Check
for
obstruction
in’
Defective
Fuel
Pump
electric fuel
pump
screen
Check
en-
gine
fuel
pump
diaphragm
and
check
valve
~I Pressue
low
or
pressure
Obstruction
in
inlet
side
Check
lines and
remove
obstruc-
srrrge
of
pump
tions
Faulty
diaphragm
in
En-
Replace
or
rebuild‘pump.
gine
pump
Check
bPel
lines
and
repair
or
tighten
-44-
C
OLDWILLWAYNE