P
air, they can also be cleaned by carefully blowing
through with compressed air after every 3000
miles. Blow from the inside out but do not hold
the compressed air nozzle too near.
Make sure that the gaskets are fitted correctly
when re-assembling. The ventilation holes (3, Fig.
11 and 2, Fig. 6) must not, under any circum-
Apart from the points shown below we refer you
to the fault tracing table in the Service Manual
for PV Part 1, B 16 A Engine where this applies.
Before the carburetors are examined in detail, ele-
mentary precautions such as checking that the
Blocked oil filter element.
Faulty valve in oil filter.
CAUSE
Pistons chafing in the carburetors. The pistons are
not going down until they meet the bridge.
I ncorrectly centred jet hampering fuel needle
movement.
The cold starting device is not taking the jet
down to its lowest position.
Uneven
No oil in the carburetor damping devices, the
fuel mixture obtained when the accelerator pedal
is rapidly depressed being too lean.
Excessively lean fuel-air mixture.
Poor synchronization of carburetors.
2 14
FAULT TRACING
FAULT
stances, be blocked since this can prevent the
carburetor in question from operating correctly.
Fuel
Since this engine has a comparatively high com-
pression ratio, fuel with an octane rating of 93
(Research) should be used.
fuel is reaching the carburetors, that the spark
plugs are working correctly and are receiving
electric current, that all the controls are func-
tioning properly, etc., should be carried out.
REMEDY
Low oil pressure
Replace oil filter element.
Check valve and replace if necessary.
The engine will not idle properly or is difficult to start
Check the movement of the pistons with the aid
of the pin on the air intake. Dismantle and clean
the pistons if required.
Centre the jet.
Adjust the controls and cable attachments in the
carburetor levers. See under the heading "Rapid
idling and choke control mechanism".
acceleration
Top-up with SAE 20 oil in the damping cylinders.
Adjust the vertical setting of the jet. See under
the heading "Idling settings and coupling of car-
buretors".
Check the position of the fuel needle. See
"Replacement of fuel needle".
Connect together the carburetors when the pass-
age of air through each of them is equal. See
"Idling adjustment and coupling together of car-
buretors".