FUEL EQUIPMENT
To Prime Feel System :
Prime the fuel system by removing ALL air :
With fuel tank filled, prime filter by unscrewing vent screws an top of fuel filter until all air is released and oil flows freely. Retighten vent screws.
Vent fuel pipe at fuel pump. Tom engine as for starting, i.e, 3 to 20 turns until injector "creaks ", and then attempt to start the engine. If the engine fails to start a more detailed method of priming must be used as; follows :
With cut-off hand lever in "STOP" position disconnect fuel injection pipe from delivery solve holder on fuel pump by unscrewing union.
Fuel Pump Fault Location :
FAULT PROBABLE CAUSE SUGGESTED REMEDY
Pump does not deliver fuel. Fuel Tank empty.
Fuel inlet pipe chocked or filter element dirty.
Air lock in pipe line.
Delivery value remains suspended.
Partly unscrew vent plug and turn engine until fuel flows freely, without any air bubbles.
Remove and examine valve face and guide, as well as seating face. If either is damaged, the pair should be replaced.
The pump does not deliver fuel uniformly. Supply of fuel to pumps insufficient.
(a) Inlet pipe chocked or filter element dirty.
(b) The "head" between the tank and the pump is too small.
Air lock in pump shown by air bubbles issuing when the delivery value holder has been unscrewed.
Delivery valve spring broken.
Delivery valve damaged either on face or guide.
Increase of "head".
Proceed as at 3.
Replace.
Fit new pair (i.e. new valve and seating complete).
Pump delivers insufficient fuel. Delivery valve leaky.
Leaky joints in the pressure system.
Fit new pair (i.e. valve and seating).
Clean joint faces and tighten down.
To Adjust Fuel Pump Linkage (12/2 & 16/2 Engine) :
Fuel pumps are calibrated as indicated by two center punch marks on the fuel pump rack. When these are equally disposed about the rack facings on the pump body, the pump is delivering fuel corresponding to full power The procedure for adjustment is as follows :
Ensure that both injectors are working satisfactorily.
Ensure that compression on both cylinders is satisfactory, if not engine should be decarbonised.
Remove split pin from joint pin and remove joint pin from upper governor connecting rod fork on right hand fuel pump, looking at engine from governor linkage side. Pull back governor connecting rod so that upper fork clears; governor upper lever.
Loosen lockout on governor connecting rod and adjust fork by screwing up or down so that on re-assembly of governor fork onto upper lever and after insertion of joint pin, it is possible to lift cut-off hand lever to fullest extent, without straining linkage and further when in this position, by applying pressure to the end of the fuel pump rack, a slight movement is obtainable.
Re-assemble complete the upper fork as described under 3 reversed. versed. Tighten lockout ensuring fork is free on governor lever.
Remove split pin, joint pin and fork from governor bottom lever and/or governor upper lever on left hand fuel pump and adjust either one or both of these as required, to obtain both pump racks in the same position in relation to pump bodies on both fuel pumps. This can be checked by setting the center punch marks on the racks of the pumps equally for both pumps. When this has been achieved, it is important to observe that the governor rods screwed end, are not the forks by a distance not less than the diameter of the rods, This can be effected by screwing up or down the forks on the bottom and upper left hand levers equal amounts in opposite directions, without changing the relative pump rack positions. Reassemble split pins and tighten up lockouts.
Start engine and put on full load. An approximate check that the cylinders are equally loaded run be found when engine is cold by starting it under load and by testing hands on cold exhaust manifolds, note which manifold warms up fastest and adjust pump racks accordingly. If engine speed falls off shorten governor links equally on both pumps half a turn at a time. Exhausts from both cylinders should remain clear, if not engine is running on overload and forks should be unscrewed equally on both pumps. N.B. - It is most important to ensure, with engine running on no load (and with racks set as above for full load), with engine running at correct speed, that there is still about ¼" free play on fuel pump racks, otherwise engine may 'race' at no load.
FUEL EQUIPMENT > FUEL INJECTOR
Fuel Injector :
Examine the nozzle if trouble is suspected and clean if necessary. The use of absolutely clean fuel ensures the maximum of time with trouble free injectors. The injectors should be set to 90 atmosphere for 6/1, 8/1 and 12/2 engines and 150 atmospheres for 16/2 engines.
A faulty nozzle may result in one or more of the following :
Smoky exhaust (black)
Engine overheating
Loss of power
Increased fuel consumption.
Knocking in the cylinder .
To test a nozzle, remove from cylinder head and reconnect to fuel injection pipe with nozzle exposed. Tom the engine until, the nozzle sprays into the air away from the operator (the spray will easily penetrate the skin of the hands) when it will be seen if the spray is streaky or dribbling; a perfect spray is in the form of a fine mist.
The nozzle must only be cleaned with the necessary special tools and by a qualified service engineer.
Remove nozzle and valve, replace with a new pair and return the defective unit to a service depot for attention.
IMPORTANT :
Apart from the attention giver. to the fuel pump delivery valve and the changing of defective injector nozzles and valves, ALL other work on the fuel injection system must be carried out by suitably equipped service depots.
