FUEL
SYSTEM
turns passes into the lower body of the
petrol pump below the diaphragm assembly
and by action
ofthe latter is pumped out
by way of the breather hole.
To obviate tlus condition an oil seal is
fitted round the diaphragm assembly push
rod and is prevented from rising
with
the
action of the push rod by a metal retainer
staked to the lower pump body.
Petrol pumps fitted with this oil seal were
fitted to engines after
No.
TS.2074E.
E
W-Io
PR,H8NC
LIYII1
During dismantling this oil seal should not
be removed unless it is known to be
Fig.
3
Section
view
of Petrol Pump.
defective.
Whenthe carburettor float chambers are
full
the float will rise and shut the needle valve,
TO
CLEAN
THE
mTER
thus preventing any flow of petrol from the
pump chamber
(M).
This will hold The pump filter should be examined every
diaphragm
(A)
downward against spring
1,000 miles and cleaned if necessary.
pressure
(C),
and it will remain in this
position until the carburettors requires Access to the filter is gained by loosening
further petrol and the needle valve opens. the thumb nut situated below the glass
The rocker arm
(D)
operates the connecting sediment chamber at the side of the petrol
link
by making contact at (R) and this pump body and swinging the wire frame to
l
NOTATION
FOR Fig.
3.
Ref.
No. Description
A
Diaphragm assembly
C
Diaphragm spring
D
Rocker arm
E
Rocker arm fulcrum pin.
F
Diaphragm pull rod.
G
Engine camshaft.
H
Fuel pump cam on camshaft.
J
Inlet port.
K
Sediment chamber.
L
Filter gauze.
M
Pump chamber.
construction allows idling movement of the
rocker arm when there is no movement of
the
fuel pump diaphragm.
Spring
(S)
keeps the rocker arm (D)
in
constant contact with cam
(H)
and elimin-
ates noise.
17.
PETROL PUMP OIL
SEAL
During very fast cornering oil rises up the
cylinder block walls and during right-hand
Ref.
No.
Description
N
Inlet or suction valve.
O Outlet or delivery valve.
P
Outlet port
R
Contact point between rocker arm and
link
lever.
S Rocker arm spring.
W
Link lever.
X
Oil seal and retainer. Petrol pump
with
this oil seal were fitted to engines after
No. TS.2074E.
one side. The sediment chamber
can
be
removed followedby the cork gasket and
gauze filter.
The gauze filter should be cleaned by a
blast of air or washing it in clean petrol.
The cork gasket should be inspected for
condition and replaced
if
broken or hard.
The glass sediment chamber should be
cleaned and its upper rim inspected for
chips.
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