Article Index
Austin Ten-Four Handbook (1935 Litchfield)
The New Car
Periodical Attentions
The Fuel System
The Carburetter
The Sports Model
The Ignition System
The Cooling System


THE supply of petrol to the carburetor is pumped from the tank at the rear. The pump operates automatically and delivers the petrol to the carburetor in the exact quantity demanded, neither more or less : an automatic mechanism accurately governs the operation.

By revolving shaft (G) the eccentric (H) will lift rocker arm (D), which is pivoted at (E) and which pulls the pull rod (F), together with diaphragm (A) downward against spring pressure (C), thus creating a vacuum in pump chamber (M).


The Petrol Pump

Fuel from the rear tank will enter at (J) into sediment chamber (K) and through filter gauze (L) and suction valve (N) into pump chamber (M). On the return stroke, spring pressure (C) pushes diaphragm (A) upward forcing fuel from chamber (M) through pressure valve (0) and opening (P) into the carburetter. When the carburetter bowl is filled the float in the float chamber will shut off the inlet needle valve, thus creating a pressure in pump chamber (M). This pressure will hold diaphragm (A)
downward against the spring pressure (C) and it will remain in this position until the carburetter requires further fuel and the needle valve opens. The rocker arm (D) is in two pieces, the outer
operating the inner one by making contact at (R) and the movement of the eccentric (H) is absorbed by this " break " when fuel is not required.

Spring (S) is merely for the purpose of keeping rocker arm (D) in constant contact with eccentric (H) to eliminate noise.

There are few moving parts in the pump apart from two automatic valves, two springs and a diaphragm, consequently, dismantling becomes an infrequent requirement. In the event of failure of any part, the replacement is easily obtained from any Austin dealer or any authorised service station of A.C. petrol pumps, who are prepared with parts and fixtures for repairing these pumps.

There are some service operations which can, if necessary, be done without referring to the dealer or service station ; and these are as follow :


Check and follow instructions :—
Petrol tank empty.—Refill.
Leaky tubing or connections.—Replace tubing and tighten all pipe connections at the fuel pump and petrol tank.
Bent or kinked tubing.—Replace tubing.

Filter Cover Loose.—Tighten the nut, making certain that the cork gasket lies flat in its seat and is not broken or unduly compressed.

Dirty Filter Screen.—Remove the filter cover and clean the screen. Make certain that the cork gasket is properly seated when re-assembling and that the fibre washer is under the head of the screw.


Loose Cover Screws.—Tighten the cover screws alternately and securely. CAUTION : Do not dismantle the pump body. NOTE.—Sometimes there appears to be a leak at the diaphragm, whereas the leak actually exists at one of the pipe fittings and the fuel has run down the pump to the diaphragm flange, appearing to originate there.

Carburetter Needle Valve not Seating.—Check carburetter for proper adjustment.

IMPORTANT. Do not attempt to disassemble the fuel pump further than described above, because it is absolutely necessary to use a special fixture in re-assembling the pump when once taken apart. When the above remedies do not correct the condition, replace with a new fuel pump sending the old fuel pump to your nearest A.C. service station.


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