The fuel system comprises the tank, pipe lines, sediment bowl, pump, carburettor and air cleaner. It is most important that the system be kept clean and free from water; periodically inspect for leaks.

Should the vehicle be stored for an extended period, it is well to completely drain the system to prevent the formation of gum which may cause trouble in the pump and carburettor. To effect complete draining, remove the drain plug in the bottom of the tank and replace when the tank is empty (Fig. 5); then rut~ the engine until the petrol in the pipes and carburettor is used up.

FUEL TANK.
Petrol is carried in a tank below the front seat-box on the right-hand side. It rests
in a stout steel cradle which forms a double bottom and protects the tank proper from damage by stones thrown up from the wheels or contact with any obstacle. The cradle is carried up both in front of and behind the tank, lipped over and bolted to the brackets on the chassis frame, thus relieving the tank of any strain due to possible slight distortion of the chassis frame under extreme conditions of use.

The filler is readily accessible by lifting the lid in the top of the seat-box on the fight-hand side (Fig. 4); a strap is provided on the back-rest panel to hold the lid in the open position. Turn the cap in an anti-clockwise direction to lift it off, which action will reveal a filler tube which can be drawn out and locked by a slight movement to the left, to facilitate filling. Care should be taken to prevent the entry of water or foreign matter. The capacity of the tank is 10 Imperial gallons (45 litres). The filler tube may be completely withdrawn to clean the gauze filter in its lower end; a drain plug is provided in the bottom of the tank. The petrol level unit is mounted in the top of the tank and requires no attention.

SEDIMENT BOWL.
Inserted in the feed pipe from the tank to the pump is a sediment bowl mounted on the right-hand side of the scuttle. Any foreign matter in the fuel settles in the glass bowl which can be removed for cleaning in petrol by slackening the thumbscrew below the bowl and swinging aside the wire holder. A fine gauze will be found in the body of the unit; this should also be removed and washed in petrol. When re-assembling, take care to replace the gauze correctly over the square inlet nozzle, and also ensure that the cork sealing washer for the bowl is in good condition.
The sediment bowl should be inspected and cleaned if necessary at the same intervals as the petrol pump filter, i.e., at every 6,000 miles (10.000 Km.).

Fig. 16. Sediment bowl.

A-Thumbscrew
B-Glass bowl. E-Fuel inlet.
C-Joint washer. F-Shut-off tap.
D-Filter gauze (fuel outlet).

A screw-down petrol supply shut-off tap is incorporated in the top of the sediment bowl and this will normally be left in the "ON" position; it is not necessary to close the tap when parking the vehicle, but this action would serve as a precaution against theft.

FUEL PUMP.
The S.U. electric fuel pump is mounted on the scuttle; it is wired through the ignition and hence will only operate when the ignition switch is "ON." Easy starting of the engine is assured, as the pump fills the carburettor float chamber immediately the ignition is switched on.
The pump is of the diaphragm type and will give prolonged service with the minimum of attention.
A gauze filter (A) is incorporated which can be easily withdrawn by unscrewing the hexagon brass plug (B) in the bottom of the pump body. The only maintenance normally required is the cleaning of this filter at every 6,000 miles (10.000 Km.); clean thoroughly in petrol using a stiff brush, never use rag.
Should fuel pump trouble be suspected, first disconnect the union at the pump end of the pipe from the pump to the carburettor and switch on the ignition. Satisfactory performance of the pump will then indicate that the fuel shortage is due either to blockage of the flexible pipe to the carburettor, or more possibly to the carburettor float needle sticking up. If the pump will not function proceed as follows -
(i) Check that the pump filter is clear.
(ii) Detach the sediment bowl and clean if necessary.
(iii) Check that the pipe from the pump to the sediment bowl is clear by blowing down it with a tyre pump from the fuel pump end.
(iv) Check that the pipe from the sediment bowl to the tank is clear by blowing from the bowl end.
(v) Reconnect the pipes and replace the sediment bowl. (vi) Test the system for correct functioning.

Should the pump still not work satisfactorily, it may be due to a poor electrical connection or dirty contact points, which should be checked as follows -
(i) Disconnect the feed wire from the terminal {D) on the bakelite cover and strike it against the scuttle ; the appearance of sparks will indicate that the current supply is in order.
(ii) Remove the bakelite cover and touch the terminal with the lead. If the pump does not operate when the points are in contact and a spark cannot be struck off the terminal, it is probable that there is some dirt on the points (F). These may be cleaned by inserting a piece of card between them, pinching them together and sliding the card backwards and forwards.

Failure to rectify the trouble with this treatment will indicate that the pump itself is at fault, due to there being too much tension on the diaphragm. To release this tension, remove the body from the base of the pump by undoing the small screws which hold these two parts together. (The pump earth wire will be released from one of these screws). The diaphragm (G) will be adhered to the body of the pump and must be separated with the aid of a knife; care should be taken to prevent the diaphragm support rollers (H) from falling out during this operation. Replace the body on the pump base and assemble the screws loosely; before finally tightening it is advisable to stretch the diaphragm to its highest possible position by switching on the pump and holding the contact points together whilst tightening the screws.

Fig. 17. Fuel pump.

A-Gauze filter
H-Diaphragm rollers.
B-Filter plug.
J-Inlet union.
C-Earthing terminal.
K-Outlet union.
D-Feed terminal.
L-Valve cage.
E-Bakelite cover.
M-Thick orange washer.
F-Contact points.
N-Thin red washer.
G-Diaphragm.

If at any time the pump becomes noisy in operation an air leak on the suction side is indicated. The simplest way to check this point is to disconnect the flexible pipe from the carburettor and allow the pump to deliver into a can. If the end of the pipe is then submerged in the petrol and bubbles appear, it indicates an air leak which must be found and cured.

If the pump keeps on beating without delivering any petrol, it is possible that a piece of dirt is lodged under one of the valves. To locate and remove such an obstruction, unscrew the top union (K) and lift out the valve cage (L) When replacing it see that the thin hard red fibre washer (N) is below the valve cage and the thick orange-coloured one (M) above. A choked filter or au obstruction on the suction side will make the pump get very hot and eventually cause a failure.

The operations outlined above should effectively remedy any trouble likely to occur; if difficulty is still experienced, your local agent should be consulted.

AIR CLEANER.
A small centrifugal pre-cleaner separates out the coarser particles of foreign matter before the air passes into the top of the main cleaner body. The air is diverted down a large diameter tube in the centre of the cleaner, at the bottom of which a sharp reversal of direction takes place, thus depositing the majority of the dust into the oil reservoir in the detachable tray forming the bottom of the cleaner. It then passes up through the woven steel packing which fills the annular chamber surrounding the central tube, where the remaining articles are extracted and the clean air travels through the outlet elbow to the carburettor intake. (Fig. 18).
The complete cleaner may be removed from, the vehicle by undoing the three large clips securing it to the support on the battery box. It is also necessary to disconnect the outlet elbow from the carburettor duct, by releasing the two wing nuts.

Fig. 18. Air cleaner.

A-Path of air shown
B-Centrifugal pre-cleaner.
C-Oil bath.
D-Oil level.
E-Woven stee lpacking.
F-Outlet to carburettor.

The oil bowl forming the bottom of the cleaner is secured to the body by means of three further (small) clips; when replacing the bowl, align the white marks on the, cleaner body and bowl to ensure correct location of the clips. The correct oil level in the bowl is indicated by a ring formed in the pressing; the capacity is approximately 2 pints (1 litre).
Two engine breather pipes from the crankcase and top rocker cover are led into the carburettor duct.
Attention to the air cleaner is extremely important, especially under dusty conditions, as it plays a very important part in preventing engine wear generally and cylinder bore wear in particular. If the vehicle is used mainly for road work, the oil bowl should be emptied, cleaned and refilled to the level mark with engine oil at each engine oil change; at the same time clean the filter gauze by swilling the cleaner body in petrol. When the vehicle is used for field work, clean and change the oil in the cleaner much more frequently; under extremely dusty conditions, such as harrowing or scuffling, daily oil changes may be required.

CARBURETTOR.

The Solex carburettor, type 32 PBI2, is fitted with a bi-starter and a two-phase acceleration and economy device, the operation of the bi-starter being fully described in the "STARTING PROCEDURE" section. No adjustment is normally required to the carburettor and the only manual setting provided is that to obtain smooth engine idling.

Slow-running adjustment.
Prior to making this adjustment it is important to ensure that the engine is in good mechanical condition; the compressions should be equal, the ignition system in order and the inlet manifold free from air leaks. The throttle " pull-off spring must pull the throttle right back to its stop, i.e., closed position; also make sure that the volume control screw (W) has not been broken or distorted by over-tightening, in which case a replacement must be obtained. (Fig. 19).
Then proceed with the adjustment as follows -
1. Run the engine until it is hot-never set the idling with a cold engine.
2. Set the slow-running screw (A) until the idling is on the high side.
3. Slacken the volume screw (W) until the engine begins to hunt.
4. Screw it in very gradually until the hunting just disappears.
5. If the engine speed is too high, reset the slow-running screw to slow it down to an idling speed of about 500 R.P.M.
6. This may cause a resumption of slight hunting. If so, turn the volume control screw gently in a clockwise
direction until the idling is perfect.

Fig. 19. Carburettor.

A-Slow-running screw.
D-Main jet. g-Pilot jet.
Gp-Pump jet.
Gu-Economy jet.
Gs-Starter petrol jet.
L-Accelerator pump operating lever.
Q-Accelerator pump operating rod.
W-Volume screw

Carburettor jet cleaning.
Reference is made in the "IN CASE OF TROUBLE" section on Pages 78 and 80 to carburetor jet cleaning.

It is most unlikely that trouble will be experienced with blocked jets, but Fig. 19 will help you to locate and remove the jets which may need cleaning. These are -
(i) Main petrol jet, the jet proper is screwed in to the inner end of the carrier (D), which must be removed to gain access to the jet.
(ii) Pilot jet (g) has a screwdriver slot in the hexagon head.
(iii) Accelerator pump jet (Gp) is located between the main and pilot jets.
(iv) Economy jet (Gu) is located at the side of the accelerator pump housing, opposite the pump jet.
(v) Starter petrol jet (Gs) is a plain hexagon-headed unit at the rear of the carburettor.

STEERING

The Burman steering gear fitted to this vehicle is of the worm and nut type, the inner column having a multi-start thread on which operates a cylindrical nut made of a special bronze alloy. The nut is free to move longitudinally in the main steering box housing, while in the side of the nut is a hardened steel bush in which operates a ball-headed extension of the rocker shaft. This latter is set at right-angles to the nut and carries the drop arm at the other end.
All end thrusts are taken by a three-piece fully adjustable ball bearing situated at the top of the steering column immediately under the steering wheel.

Fig. 20. Steering gear.

A-Oil filler plug.
B-Lock-nut.
C-Adjusting nut.
D-Felt washer.

STEERING COLUMN ADJUSTMENT.
The only adjustment provided is to the top journal bearing. This consists of a cup secured by a lock-ring in the top of the outer column and two races, the lower one being fitted to the inner column before assembly, after which the balls are put in place and the top race adjusted by a hexagon nut and lock-nut.
Wear or end play on the inner column can therefore be taken up by first partially drawing away the steering wheel to allow access to the lock-nuts; then unscrew the top nut, pull down the lower nut until end play disappears and finally screw down the lock-nut absolutely tight.
The adjustment just described should rarely need attention and no other part of the gear calls for adjustment. Should the occasion arise to remove the drop arm, care should be taken not to damage the felt washer; if it becomes damaged a replacement should be obtained.