1973 OPEL MANTA carburetor

The 1973 Opel Chassis Service MayI has been completely revised with respect to layout, format and information content
in a” attempt
to provide you “The Technician” with a tiore logical and usable publication. An example of the new grouping
layout 6 exhibited on the preceding
page. Each wow is rubdivided as follows:
Grouo 1
_. _
Subiect IIContents.
0
General InformationIGeneral InformationLifting
Maintenance and Lubrication
1ElectricalBattery
Starting System
lgriition System
Charging System
Washers and Wipers
Lighting Systems
Signal SystemI
Instrument Panel
Gauges
Wiring Diagrams
2
Body and Bumpers:General Body InformationI
Frame & Body Mountings
Windows
& Window Moldings
DONS
Rear Compartment LidRoof &Sun Roof
Seat?., Interior Trim & Headlining
Bumpers.
3Suspension and Steering
Front Suspension
Steering Linkages1Front End Alignment
Steering Gear
Steering Column
Rear Suspension
Wheels and Tires
4
Propelley Shaft & Rear AxlePropeller Shaft & Central Joint
Differential
5Brakes ~Power Booster and Master Cylinder
Front Disc BrakeI
Rear Drum Brake
6EngineEngine Mechanical and Mounts
Cooling System
Fuel System
Exhaust Systems
Carburetor and Throttle Linkage
Emission Control Systems
Tune-up
7TransmissionClutch
Manual Transmission
Automatic Transmission
BChassis Sheet MetalHood, Fenders and Grille
9
Accessol;iesHeaterAirConditioning
Radio

LUBRICATION AND MAINTENANCE OC-11
Throttle Linkage
Check for damaged or missing parts, interference or
binding. Any deficiencies should be corrected with-
out delay.
Headlights
Check for proper aim. Correct as necessary. More
frequent checks should be made if oncoming motor-
ists signal when you are already using your low
beams, or if illumination of the area ‘ahead seems
inadequate.
Underbody
In geographic areas using a heavy concentration of
road salt or other corrosive materials for snow re-
moval or road dust control, flush and inspect the
complete under side of the car at least once each
year, preferably after a winter’s exposure. Particular
attention should be given to cleaning out underbody
members where dirt and other foreign materials may
have collected.
EMISSION CONTROL MAINTENANCE
Thermostatically Controlled Air Cleaner
Inspect installation to make certain that all hoses and
ducts are connected and correctly installed. Also,
check valve for proper operation.
Carburetor Choke
Check choke mechanism for free operation. A bind-
ing condition may have developed from petroleum
gum formation on the choke shaft or from overtight-
ening of air cleaner clamp. Also check electric choke
terminal connections and fuse.
Timing, Dwell and Distributor
Adjust timing and dwell accurately as outlined under
Tune-Up in Group 6 at the first 4 months or 6,ooOmiles of operation, then at 12 month or
12,OQO mile
intervals. Adjustments must be made with test equip-
ment known to be accurate.
Replace distributor points every 12 months or 12,000
miles and carefully clean and inspect the complete
distributor cap to prevent misfiring and deteriora-
tion.
Carburetor and Idle
SpeedTorque carburetor attaching bolts and/or nuts to 12
ft.lbs. to compensate for compression of gasket atiirst 4 months or 6,000 miles of vehicle operation.Adjust idle speed to specifications with known accu-
rate equipment.
Proper functioning of the carburetor is particularly
essential to control of emissions. Correct mixtures
for emission compliance and idle quality have been
preset by Opel. Plastic idle mixture limiters have
been installed on the idle mixture screw, idle air
screw, and throttle stop screw to preclude unauthor-
ized adjustment. The plastic caps on the idle mixture
screw and the idle adjustment screw must be
removed to perform an idle speed adjustment. The
plastic cap on the throttle stop screw is not to be
removed unless some major carburetor repair or re-
placement which affects the throttle stop screw ad-
justment has been necessary.
Carburetor Fuel Inlet Filter
Replace filter at 12 month or
12,OCO mile intervals
or more often if clogged.
Spark Plugs
Replace at
6,ooO mile intervals when operating with
leaded fuels or at 12,000 mile intervals when using
unleaded fuels. Use of leaded fuels results in lead
deposits on spark plugs and can cause misfiring at
mileages less than
12,OilO miles. Where misfiring oc-
curs prior to
6,ooO miles, spark plugs in good condi-
tion can often be cleaned, tested and reinstalled in an
engine with acceptable results.
Spark Plug Wires
Inspect spark plug wires for evidence of checking or
cracking of exterior insulation and tight fit in the
distributor cap and at the spark plugs. Exterior of
wires should be cleaned, any evidence of corrosion
on ends removed and wire replace if deteriorated.
Positive Crankcase Ventilation System
The PCV metered orifice should be cleaned at 12,000
mile intervals under normal use, and at 6,000 mile
intervals when the vehicle is used under the follow-
ing conditions: driving in dusty conditions, extensive
idling, trailer pulling and short trip operation at
freezing temperatures (engine not thoroughly
warmed-up).
Evaporation Control System
Check all fuel and vapor lines and hoses for proper
connections and correct routing as well as condition.
Remove canister and check for cracks or damage.
Replace damaged or deteriorated parts as necessary.
Replace filter in open end of canister at 24month/24,000 mile intervals.

IIIGNITION SYSTEMlC- 19
11. (Startx position.) The ignition key must be
released as soon as engine starts. The switch then
returns aujomatically to the on position.
IGNITION
GOILThe ignition coil consists of a laminated non- mag-
netic iron
(core enclosed by two coils; the primary
winding and the secondary winding.
The prim+y circuit consists of the power source
(battery), the ignition switch, the ignition coil pri-
mary winding, the distributor breaker points with
ignition condenser connected in parallel, and all con-
necting
lo& tension wiring.
The secondary circuit consists of the ignition coil
secondary ‘winding, the spark plugs, all connecting
high tens@ wiring, the distributor cap and the
ro-tor.
When the’ ignition switch is turned on and the
breaker pdints are closed, current flows through the
ignition
c&l primary winding and produces a mag-
netic field wound the coil windings.
When the breaker points are separated by the revolv-
ing distributor cam, the magnetic field collapses and
induces a high voltage surge in the secondary wind-
ing,
produ;cing a spark between the spark plug elec-
trodes. ,
The ignitidn condenser which is connected in paral-
lel with the breaker points, prevents arcing between
the
separa’ted breaker contacts, and current flow
after~ the breaker points have been separated, thus
causing a kery rapid collapse of the magnetic field
around th$ Ignition coil.
/
IGNITION ‘DISTRIBUTORThe ignitidn distributor breaks the primary current,distributeslthe high voltage surges induced in the coil
secondary winding to the spark plugs according to
the engin< tiring order and sets ignition timing in
relation to. engine RPM and load.
The housi+g of the distributor contains the centrifu-
gal advance mechanism and the movable breaker
plate with’s breaker lever and contact support. The
vacuum advance mechanism is attached to the
breaker plate and mounted on the outside of the
distributor, housing. See Figure lC-1.
The distributor shaft is driven by a helical gear on the
camshaft and in turn drives the engine oil pump. The
ignition condenser is mounted on the outside of the
housing. The engine output is to a large extent in-
fluenced b) the ignition timing. Maximum engine
performance is obtained when the combustion proc-
ess is well underway as the piston starts down on thepower stroke. The air-fuel charges are, however, not
burned instantly, so it is necessary to advance the
spark in relation to the piston top dead center as
engine speed increases or as engine load decreases.
If the spark is too far advanced, the engine knocks,
causing a drop in engine power output and overheat-
ing. If the spark is retarded, part of the energy deve-
loped during combustion is wasted which will result
in reduced engine power output, excessive fuel con-
sumption and overheating.
The ignition distributor has a double acting double
diaphragm vacuum unit. See Figure lC-1. The ad-
vance unit is supplied with “ported” vacuum. That
is, vacuum is supplied from a port in the primary
barrel of the carburetor located just above the closed
throttle valve. This port supplies no vacuum during
idling nor during closed throttle deceleration, but
supplies full intake manifold vacuum at all speeds
where the throttle valve is opened enough to uncover
the port.
Figure lC-1 Ignition Distributor
The retard unit is supplied with intake manifold
vacuum at all times by means of a line connected
directly to the intake manifold. During idling and
deceleration, when there is no vacuum to the ad-
vance unit, the retard unit will cause the timing to be
retarded 5 degrees. However, during part throttle
operation when there is vacuum to the advance unit,
the advance unit will overpower the retard unit so
that the retard unit has no effect on timing.
The purpose of the retard unit is to reduce hydrocar-
bon and carbon monoxide emissions during idling
and deceleration, where they are especially bad.
In order to avoid voltage losses for easier starting, a
plastic cover has been inserted in the distributor be-
low the rotor as a seperator to keep the inside of the
distributor cup free from condensation.

GROUP 6
ENGINESection6A
6B
6C
6D
-
6E
6F6GTitle
‘age No.
EngineMechanical and Mounts
AllModels
Cooling System
AllModels
. . . . . . . . . . . . . . . . . . . . . .
Fuel SystemAll
Models. . . . . . . . . . . . . . . . . . . . . . . .
Exhaust Systems
AllModels
. . . . . . . . . . . . . . . . . . . . . . . .
Carburetor
And
ThrottleLinkage
. . . . . . . . . . . . . .
Emission Control
Systems
- All Models . . . . .6A- 2
6B-326C-366D-42
6E-446F-60
Tune-Up
AllModels
. . . . . . . . . . . . . . . . ..__....66-65

ENGINE MECHANICAL AND MOUNTS6A- 9
The engine does not rest on the front suspension
cross member as in the Opel 1900 and Manta but on
a separate cross member. On removal and installa-
tion of the engine the front suspension cross member
need not be detached.
Fig. 6A-10 Right Front Engine Suspension with Cross
Member
(GT)1. Disconnect battery negative cable,
2. Remove air cleaner.
3. Drain radiator coolant by disconnecting lower
radiator hose. Disconnect upper radiator hose. See
Figure 6A-11. Radiator need not be disconnected.
4. Disconnect all electrical connections:
a. Coil wire to distributor.
b. Wires from alternator. Remove unit and bracket.
c. Battery positive cable at starter switch.
d. Oil pressure switch wires at cylinder block.
e. Wires from starter solenoid.
5. Remove vacuum hoses at tee mounted to intake
manifold. Remove tee from manifold to avoid inter-
ference during engine lowering.
6. Remove throttle linkage and carburetor.
7. Disconnect heater hoses.
8. Disconnect water valve bracket to manifold,
9. Remove gear shift lever.
10. Using suitable equipment lift up engine so that
front engine mounts are somewhat relieved.Figure 6A.1
1 Radiator Hose Clamp Location
11. Raise vehicle, both front and rear end. A two post
axle type hoist
IS recommended for this operation.
12. Disconnect fuel line at fuel pump and plug. Be
sure fuel line is disconnected from any engine and
transmission clips.
13. Disconnect speedometer cable from transmis-
sion.14. Disconnect clutch cable.
15. Disconnect drive shaft at rear universal joint and
remove.
16. Disconnect exhaust at manifold.
17. Remove tailpipe and mufIler hangers.
18. Remove ground strap from engine to side rail.
19. Detach transmission cross member from trans-
mission and frame. See Figure 6A-12.
20. Detach engine cross member from engine and
frame.21. Carefully lower engine and transmission and
remove from underneath vehicle.

6A- 121973 OPEL SERVICE MANUALINTAKE AND EXHAUST MANIFOLD REMOVAL
AND
INSTALLATION
Removal1. Disconnect battery.
2. Remove air cleaner.
3. Disconnect throttle linkage at carburetor.
4. Disconnect vacuum advance line at carburetor.
5. Remove fuel line at carburetor inlet.
6. Remove positive crankcase ventilation hose at
rocker arm cover.
7. Disconnect E.G.R. lines from carburetor and in-
take manifold.
8. Disconnect exhaust pipe.
9. Remove six bolts attaching manifold assembly to
cylinder head and remove manifold and carburetor
as an assembly. Discard manifold gasket.
To separate intake and exhaust, manifold, remove
carburetor and four bolts using Tool J-23016, attach-
ing intake manifold to exhaust manifold. Always in-
stall a new manifold intermediate gasket when the
manifolds are separated.
Installation1. Install new manifold gasket and place manifold in
position.
2. Install manifold bolts. New manifold to cylinder
head gasket must be installed whenever a manifold
is removed.
3. When installing the manifold, start with the No.
1 and No. 2 bolts. See Figure 6A-16. Gradually
tighten both bolts until snug. Then continue with the
rest of the bolts in the sequence illustrated in Figure6A-16. Torque bolts to 33 lb. ft.
Figure 6A-16 Manifold
Bolt Tightening Sequence4. Connect parts removed in Steps 1 thru 8 above.
CYLINDER HEAD REMOVAL AND INSTALLATION
Removal1. Drain coolant from radiator and block. Loosen
drain plug on right side of engine to avoid coolant
entering into cylmder bores. Drain plug is located onthe right rear of cylinder block above oil pressure
switch.2. Remove hoses from thermostat housing. Collect
coolant as it contains anti-freeze.
3. Remove 6 intake and exhaust manifold attaching
bolts and swing assembly aside.
4. Remove spark plug wires from plugs.
5. Remove bracket bolt holding spark plug wires
away from cylinder head.
6. Remove rocker arm cover.
7. Remove 10 cylinder head bolts using 12 MM ser-
rated drive J-22915, and 2 cylinder head to timing
chain cover bolts with a 6MM hex head wrench. See
Figure 6A- 17.
Figure 6A-17 Serrated Bits
8. Remove three bolts attaching plate to front of
cylinder head.
9. Remove plastic screw from end of camshaft.
10. Remove 3 bolts attaching camshaft sprocket to
cylinder head. Slide sprocket off of camshaft and
remove head. Place head on bench supported at each
end by a block of wood to prevent damage to valves.
Installation1. Install in reverse procedure to removal, paying
particular attention to the following:

6C- 361973 OPEL SERVICE MANUAL
FUEL SYSTEM
ALL MODELS
CONTENTS
Subject
DESCRIPTION AND OPERATION:
Fuel Pump. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . .Evaporation Control System
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .DIAGNOSIS:
(Not Applicable)
MAINTENANCE AND ADJUSTMENTS:
Cleaning Fuel Pump Strainer.,....................................
*.Evaporation Control System
. . . . . . . . . . . , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .MAJOR REPAIR:
Fuel Tank
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Fuel Lines and Fuel Tank Gauge Units
. . . . . . . . . . . . . . . . . . . . . .SPECIFICATIONS:
Fuel System Specifications
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page No.6C-366C-376C-376C-386C-396C-416C-41
DESCRIPTION AND OPERATION
FUEL PUMPThe 1.9 liter engine uses a push rod type fuel pump.
The push rod is actuated by an eccentric on the
distributor shaft. The push rod is held in contact
with the eccentric at all times by a push rod spring.
Each time the push rod is on the high part of the
eccentric, the lighter diaphragm spring will push the
diaphragm to replace any fuel used in the carburetor.
The diaphragm seldom operates through a full
stroke; under normal driving conditions, the dia-
phragm moves only a few tenths of an inch.
Fuel pump pressure is determined by the compres-
sion of the diaphragm spring. Low pressure or pres-
sure leak- down generally indicates a leaky
diaphragm or check valves.
Two holes in the lower part of the fuel pump serve
to ventilate the space below the diaphragm and to
drain any fuel which may have entered. If any fuel
comes from these holes, this indicates a defective
diaphragm.When replacing the fuel pump, make sure the asbe-
stos spacer is in place with a gasket on each side. See
Figure 6C- 1. Because of the location of the fuel pump
eccentric on the distributor shaft, the fuel pump
Figure
6C-1 Installing Push Rod Type Fuel Pump

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