fuel pump OPEL 1900 1973 User Guide

FUEL SYSTEMSC- 37
must always be removed before the distributor can be
removed.
EVAPORATION CONTROL SYSTEM1. The function of the fuel evaporation control sys-
tem is to absorb the fuel vapors developing in the fuel
tank, especially when vehicle is parked, due to at-
mospheric pressure and temperature influences, and
to release these fuel vapors during vehicle operation.
2. This system utilizes the property of the activated
carbon to absorb and expel fuel vapors. The activated
carbon container is installed on the left front side of
the engine compartment. The fuel tank has a
non-vented tiller cap. Vent hoses are joined in the area of
the tank. A plastic evaporation line leads from there
along vehicle underbody to the activated carbon con-
tainer.
3. A small tube above the throttle valve body con-
nects the carburetor to the activated carbon con-
tainer. In this way, the fuel vapor collected in the
activated carbon container is fed through the carbu-
retor into the combustion chambers during engine
operation.
4. The carburetor is provided with an internal and
outside ventilation, the activated carbon container is
also connected to the outside ventilation (only effec-
tive when engine is idling). In this way, the fuel
vapors escaping to the outside during engine idle are
collected by the activated carbon container and fed
into the combustion chambers.
5. The vent lines are connected to the upper part of
the activated carbon container. Fresh air enters
through a foam rubber filter at the lower part andflows, together with the fuel vapor, to the carburetor.
Metered bores in the hose fittings of the fuel tank
control the air
- and fuel vapor flow through the
activated carbon container to the carburetor, and the
pressure release in the fuel tank and ensure complete
purging of the carbon container.
Care must be taken not to mix up lines at the ac-
tivated carbon container. See Figure
6C-2.6. The metered bores in the fuel tank fitting and an
overflow protection in the fuel tank, which prevents
a complete filling of the tank, prevents fuel flows into
the activated carbon container rendering it useless.
FUEL FILTERAn AC fuel filter type (GF 423) is being used on all
1973 Opels. A vapor return line returns vapors in the
fuel line back to the fuel tank. Proper installation of
the filter is essential. The vapor return line connector
must be on top (highest point) for proper operation.
See Figure
6C-3.1. LINE TO
CARBURETOR2. FILTER
3. LINE FROM
4. VAPOR
RETURN LINE
6C-3Figure
6C-3 Fuel Filter
MAINTENANCE AND ADJUSTMENTSFigure
6C-2 Carbon CanisterCLEANING FUEL PUMP STRAINER

6C- 381973 OPEL SERVICE MANUALCAUTION:Because the fuel pump is below fuel tank
level, fuel
will drain from the tank. when the supply
hne is disconnected from the fuel pump.1. Pull fuel supply line and rubber connector from
fuel pump. Plug rubber connector to prevent fuel
loss.2. Remove fuel pump cap, gasket and plastic
strainer.
3. Cover center opening in sediment bowl with finger
and blow out sediment bowl with compressed air.
4. Wash plastic strainer in solvent; if strainer does
not clean-up or is damaged, replace strainer.
5. Install clean parts, noting the following:
(a) Strainer must be properly seated with projections
facing upward.(b) A new cap gasket must be positioned over
strainer.
(c) Sealing ring must be in place on cap retaining
screw.6. Reconnect fuel supply line. Start engine and check
for leaks.
EVAPORATION CONTROL SYSTEMProper performance of the system requires the use of
a non-vented fuel tank cap, hose connections be leak-
free, and all hoses routed correctly to avoid a
pinched or blocked line.
Maintenance requirements demand only that the ac-
cumulator purge air tilter, an oiled foam filter assem-
bled in the bottom of the canister, be replaced at
12,CKO mile intervals. Under extremely dusty condi-
tions, more frequent attention may be required.
Figure
W-4 Exploded View of Opel 1900 and Manta Fuel Tank

FUEL SYSTEM6C- 41
covered with sound deadening compound. See Fig-
ure
6C-10.7. Remove fuel tank vent hose and tiller hose. See
Figure 6C- 11.
8. Remove fuel tank attaching bolts and gauge wire
and remove tank.
Installation
1. Install tank and tighten attaching bolts.
2. Replace gauge wire. Install vent hose, making cer-
tain it is not kinked and seal vent hose hole in floor.
3. Install spare tire support attaching brackets, sup-
port panel, hold-down, and brackets.
4. Install spare tire and jack.
5. Install fuel line and rubber cap.
6. Connect battery.FUEL LINES. FUEL GAUGE TANK UNITS
All fuel lines are plastic and have an outside diameter
of
,240 inches. Unlike metal lines, plastic lines are
not flared.
When replacing a plastic line, place the line in hot
water to make it flexible. Using the old line as a
pattern, form the new line. Let the line cool com-
pletely, then route it in the same location as the old
line. To prevent chafing against the underbody, nine
(9) rubber grommets are placed at points on the line
between the fuel tank and the fuel pump. When re-
placing fuel gauge tank units, coat gasket on both
sides and first threads of attaching screws with seal-
ing compound.
CLEANING FUEL TANK
1. Remove fuel tank.
2. Empty fuel tank through filler neck.
3. Remove fuel gauge tank unit, together with suc-
tion tube and screen. Clean screen and blow out from
cover side. Flush fuel tank.
SPECIFICATIONSFuel Tank Capacity (Gallons)
Opel 1900 and Manta
....................................................................................................11.9GT
....................................................................................................................................13.2FuelGaugeType
........................................................................................................Electrical
Fuel Pump Type
......................................................................................................Mechanical
Fuel Pump Drive
..................................................................................Eccentric on Camshaft
Fuel Pump Pressure at 1950 (RPM)................................................................3.1 to 3.7 P.S.I.FuelFilter
............................................................................................................In-LineFilter

SE- 441973 OPEL SERVICE MANUAL
CARBURETOR AND THROTTLE LINKAGE
ALL MODELS
CONTENTS
Subject
DESCRIPTION AND OPERATION:
Carburetor
. . . . . . . . , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .DIAGNOSIS:
Carburetor
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .MAINTENANCE AND ADJUSTMENTS:
Idle Speed and Mixture Adjustments
. . . . . . . . . . . . . . . . . . . . . . . .Fast Idle Speed Adjustment
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Throttle Linkage Adjustment
. . . . . . . . . . . . . . . , . , . . . . . . . . . . . . . . . . . . . . . .MAJOR REPAIR:
RemoveandInstallCarburetor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I...Throttle Linkage Removal
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .OverhaulCarburetor
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .SPECIFICATIONS:
Carburetor
Specifications
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page No.
6E-44
6E-49
6E-50
6E-51
6E-51
6E-52
6E-53
6E-53
6E-58
DESCRIPTION AND OPERATION
CARBURETORThe two-barrel carburetor for all 1973 Opel1
19G0,Manta and GT models is a down-draft carburetor
with two barrels of 1.25 inch diameter each. It has
an automatic choke and a secondary valve operated
by a vacuum diaphragm, except when installed in an
Opel GT. In the GT, the secondary throttle valve is
operated by mechanical linkage from the primary
throttle valve.
The two-barrel carburetor consists of three main
parts
- throttle body, float chamber and air horn.
Each barrel is a separate system, but both barrels
discharge into a common inlet in the intake mani-
fold. The secondary barrel does not have a choke
valve or an accelerator pump. See Figure
6E-2.The throttle valve of the primary barrel is opened
through the throttle linkage. When the primary
throttle valve is almost open, at approximately half
of the maximum engine RPM, the secondary throttlevalve is opened by vacuum applied through a
vacuum diaphragm case. See Figure
6E-3. The sec-
ondary throttle valve on the GT model is opened by
mechanical linkage from the primary throttle shaft.
Choke SystemThe automatic choke is operated by a bi-metal
spring. The tension of the spring
- depending on
temperature of the heater coil
- decreases with rising
temperature and the choke valve opens progressively
until it is completely opened at engine operating tem-
perature. The choke valve is off-set so that choke
valve opening increases as air flow increases.
If the choke valve is closed, the throttle valve is
opened slightly to provide a fast idle speed. This is
done through a cam, abutment lever and throttle
connecting link. With the throttle valve opened
slightly, the vacuum during cranking can take effect
up to the choke valve, thereby drawing ample fuel
out of the main nozzle. See Figure
6E-4.With rising temperature of the heater coil, the choke

6E.461973OPELSERVICEMANUAL
Sectional View Of Carburetor
1Carburetor cover
2Vent valve
3 Ball valve (pressure valve)
4Injection tube
5Primary venturi
6Choke valve
7Vent
iet8 Air correction
iet9Enrichment
10 Float needle valve
11 Float needle valve seal ring12 Fuel line connecting tube
13 Carburetor cover gasket
14Leaf spring
15Float
&amber16 Pressure reduction valve17Pump lever
18Diaphragm
19 D iophragm spring
20 Ball valve (suction valve)
21Float
22 Pump connecting rod
23Metering
iet24Emulsion tube
25 Bore without function
26Throttle valve
27Intermediate lever
28Main venturl
29 Vacuum passage for automatic choke
30 Throttle valve body
31Gasket
32 Vent valve lever
Figure 6E-2 Sectional View of Carburetor

6~. 46,1973 OPEL SERVICE MANUAL
ary barrel, it is provided with g transfer system.
When the secondary throttle valve starts to open,
two‘ports (which are normally just above the closed
valve) are uncovered, causing fuel to feed into the
secondary bore just before the secondary nozzle
starts feeding. This provides for an additional enrich-
ment of the air-fuel mixture at the beginning of full
throttle operation. See Figure
6E-7.
nInFlFigure
6E-7 Primary to Secondary Transfer System
Full Thrdttle Enrichment SystemIf the secondary throttle valve is fully opened, the
vacuum in the throttle valve area is reduced so that
the transfer ports (mentioned above) stop feeding.
However, the vacuum increases greatly in the sec-
ondary venturi area. An enrichment tube which pro-
trudes into the primary venturi area, feeds fuel
continuously during full throttle operation. See Fig-
ure
6E-2.
Acceleration SystemWhenever the throttle is closing, the suction stroke
of the diaphragm pump causes fuel to flow from the
float chamber through the inlet ball valve into the
pump chamber. When the throttle valve is opened
the diaphragm is moved inward by the pump con-
necting rod and the pump lever. Fuel is injected into
the primary bore through the injector tube. The
amount of fuel is determined by the pump stroke.
The inlet ball valve in the pump chamber prevents
fuel from flowing back into the float chamber during
the pressure stroke of the pump. The outlet ball valve
prevents air from being drawn into the injector tube
during the suction stroke of the pump. See Figure6E- 8.
Float Bowl VentilationWhile driving, the float bowl is ventilated from insideFigure
6E-8 Acceleration System
the carburetor. That is, the float bowl is connected
through the vent valve with the area under the air
cleaner.
When the engine is idling or off, the ventilation from
inside is cut off and ventilation from the charcoal
canister is cut in. The upper spring now seats the
valve on the upper seat. See Figure
6E-9.
-6E-9
Figure
6E-9 Float Bowl VentilationThe advantage of an inside vent while driving is that
air cleaner restriction does not enrichen the air fuel
mixture. The purpose of the charcoal canister vent
while idling or after shutting-off a hot engine, is to
prevent excess fuel vapors from entering the intakemanifold and outside air. Excess fuel vapors may
cause an idling engine to stall, or may make it dif-
ficult to restart a hot engine.

CARBURETOR AND THROTTLE LINKAGE6E- 49DIAGNOSIS
CARBURETORCondition I
Hesitation or Stall Upon Light AccelerationCorrection
1. Check spark plugs and plug gap. Plug gap should
be
,030 in.
2. Check dwell and timing.
3. Adjust carburetor.
4. Accelerator pump should discharge fuel between
throttle plate and venturi wall with engine off. If aim
is not correct, use needlenose pliers to slightly bend
nozzle so proper aim is achieved. See Figure 6E- 10.
CORRECT ACCELERATOR
PUMP DISCHARGE
NOZZLE AIM
\Figure 6E-10 Pump Shot Aim
Road test car. If hesitation still exists, check for the
folI0 wing:1. Plugged accelerator pump discharge nozzle.2. Dirt in accelerator pump circuit.
3. Defective inlet check ball.
4. Defective accelerator pump pressure relief valve.
5. Defective accelerator pump diaphragm.
6. Maladjusted accelerator pump linkage.
Condition II
Hard Start Afier Hot Soak
CorrectionPerform Steps l-4 in Condition I.
Condition Ill
Hard Start When Engine Is Cold
Correction1. Align groove on choke cover with pointer on
choke housing. See Figure
6E-17.2. Set fast idle.
3. Replace distributor points if pitted.
4. Check spark plugs and gap at
,030.5. Set dwell and timing.
If above procedure does not correct problem, replace
with new automatic choke assembly.
Condition IV
Rough, Erratic, or No Idle
Correction1. Check spark plugs and gap at
,030.2. Check dwell angle and ignition timing.
3. Clean idle jet and passages with air hose. See Fig-
ure
6E-5.4. Check manifold to head bolt torque. Should be 33
lb.ft.5. Check automatic choke linkage alignment.
6. Adjust carburetor.

6E- 561973 OPEL SERVICE MANUAL
valve stop screw. Loosen the stop screw until the
valve is completely closed. Turn the screw in l/4turn from closed position, hold, and tighten lock nut.
This is done to insure that the throttle blade will not
stick closed. See Figure
6E-30.PUMPFigure 6E-30 Adjusting Secondary Throttle Valve Gap
24. Install accelerator pump connecting rod in lower
hole of primary throttle shaft lever and cotter pin in
outboard hole at accelerator pump actuating lever
end. Paying attention to proper arrangement of cot-
ter pin and washers. See Figure
6E-2.25. With throttle plate completely closed, there
should be no clearance between the pump levei and
the pump plunger rod.
26. If a clearance is present, loosen 4 accelerator
Figure
6E-31 Accelerator Pump CoverFigure 6C32 Accelerator Pump Cover
pump cover retaining screws and allow the
dia-’phragm spring to push plunger against lever so that
a zero clearance exists. Then retighten the screws.
See Figures
6E-3 1 and 6E-32.27. Insert accelerator pump discharge nozzle so that
the bent tube end points into suction channel of the
primary barrel.
28. Fill the bowl with fuel.
29. With fuel in bowl, slowly open the throttle and
observe the accelerator pump pressure relief valve
exhaust ports and where it seats into the bowl. See
Figure
6E-33. Fuel should not be bleeding back into
the bowl from the exhaust ports or where the relief
valve seats, but a steady stream of fuel should dis-
charge from the discharge nozzle.
30. With fuel in bowl, rapidly open the throttle atid
observe the exhaust ports of the pressure relief valve.
See Figure
6E-33. Fuel should~exhaust’from the ac-
celerator pump pressure relief valve exhaust ports.
3 1. If the pressure relief valve malfunctions, remove
it and replace with a new one.
32. No float adjustment is possible, so check position
of float arm by comparing with a new float of thesame carburetor type. If float arm is bent, replace
float.

CARBURETOR AND THROTTLE LINKAGE6E- 57
ACCELERATOR PUMP
PRESSURE RELIEF
VALVE SEAT
ALVE
VENT DISCHARGE
(AIR BUBBLES FROM THIS
HOLE
IS NORMAL)
PUMP INLET
VALVE EXHAUST
PORT
--6E-33
Figure 6E-33 Carburetor Fuel Bowl
33. Install float and pivot rod making sure rod is
seated in casting.36. Install new air horn gasket so that the holes in
the gasket coincide with the screw holes in carbu-
retor housing. See Figure
6E-35.34. Install leaf spring so that spring ends rest on float
spindle. See Figure
6E-34.37. On vent valve, pay attention to cotter pin position
and arrangement of washers.
3.5. Screw in float needle valve together with copper38. Basic adjustment of idle mixture adjusting screw
seal ring
(.08 in. thick).is 5 turns open.

6E- 581973 OPEL SERVICE MANUAL
Figure 6E-34 Leaf Spring Installed
1 6E-36
Figure 6E-36 Checking Vent Valve Adjustment
39. Check compression of vent valve lower spring. It
should be compressed
l/4 inch with throttle valve
completely closed. See Figure
6E-36.40. Correct by bending valve lever.
Figure
6E-35 Installing Cover Gasket
SPECIFICATIONS
GENERAL SPECIFICATIONSCompression Ratio
........................................................................................................7.6 to 1
Fuel Required
................................(...........................................................................Low Lead
Fuel Tank Capacity (Gallons)
Opel1900andManta..
....................................................................................................11.9
GT...................................................................................................................................13.2Fuel Gauge Type
........................................................................................................Electrical
FuelPumpType
......................................................................................................Mechanical
FuelPumpDrive
..................................................................................EccentriconCamshaft
Fuel Pump Pressure at 1950 RPM
......................................................................3.1 to 3.7 psi
FuelFilter
............................................................................................................In-LineFilter
CarburetorMakeandType................................................I-Solex2BBLAutomaticChoke
AirCleanerElementType
..........................................................................FiberMesh-Paper