SERVICE· BULLETIN
V5
DATE:
August
27,
1975
BULLETIN
NUMBER:
76
MODEL: Four-9l,
W-30
;
W-50
(If
fitted
with
thi s
type
pump)
SUBJECT:
Proper
bleeding procedure for hydraulically
governed
fuel injection
pumps
incorporating
an
engine
anti-stall
device
An
anti-stall
device
is
incorporated
on
fuel injection
pumps
fitted
to the
Four-91
engines.
This
device
is
located
on
top
of the fuel
pump
governor housing,
just
beneath
the
air
vent bleed screw.
In
fact,
the bleed
screw
and
anti-stall
device
are a
complete
assembly
incorporating parts #1,
#2,
and
#3
as
shown
on
the dia-
gram.
The
anti-stall
device
has
a spring
loaded
pin
which
comes
in direct contact,
with
the
top
end
of the fuel injection
pump
(metering valve) preventing rapid
upward
movement
of the metering valve to the fuel cutoff position, during rapid
engine deceleration.
Rapid
deceleration or rapid retarding of the
throttle
without this device installed
would
normally
cause
engine
stalling
and/or
stoppage.
It
should
be
noted
here that
under
normal
bleeding procedures,
it
is
only
neces-
sary to bleed
the
bleed
screw
#5
shown
on
the
diagram.
However,
if
excessive
air
entering the injection
pump
makes
it
necessary to
bleed
screw
#1
in the
diagram
during the fuel
pump
bleeding procedure,
when
loosening or tightening the bleed
screw
#1,
two
wrenches
should
be
used.
One
is
to
loosen
the bleed
screw
and
one
is
to
hold
the
anti-stall
device
body
#2
to prevent
it
from
turning
and
upsetting the adjustments.
If
during the bleed-
ing procedure
screw
#2
shown
in the
diagram
is
inadvertently turned in or clock-
wise
during bleeding the result will
be
excessive engine
RPM
which
cannot
be
controlled
by
retarding the
throttle.
If
the adjustment of the
anti-stall
device
has
been
disturbed or
when
installing
a replacement
pump,
the procedure for resetting
it
is
as
follows:
1.
Loosen
the locknut
(#3)
sufficiently to enable the
anti-stall
device
body
(#2)
to
be
unscrewed
two
complete
turns.
2.
Set engine idle
speed
with
idling stop
screw
(#4)
to
800
RPM.
3.
Turn
the
anti-stall
device
body
(#2)
clockwise until there
is
a barely
perceptible increase in the idling speed.
Now
hold
device
body
(#2)
with
wrench
and
tighten locknut (#3).
4.
Accelerate the engine to
maximum
no
load
RPM
and
return the
throttle
rapidly to the idling position.
Should
the period of return
from
maximum
RPM
to idling
RPM
speed
exceed
three seconds, this
is
an
indication that the device
has
been
screwed
in
too
far.
However,
should
engine
stalling
occur, this is
an
indication that the device
PIN:
19329
J. H. WESTERBEKE CORP.
AVON
INDUSTRIAL
PARK,
AVON,
MASS.
02322·
(8171588-7700
CABLE:
WESTCORP,
AVON·
TELEX:
112-
........
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