1977 xj6 4.2 fuel leak

car not running for 16 years.tank full of debris,cleaned it up and installed new pumps(was running car from a fuel container with no issues)starts well but after a few minutes cuts out.fuel leaks from bottom of canister(front right wheel) and left overflow hose,what do i do please?

Hi Henry, welcome to the forums.
Sorry to hear you are having troubles.
We need a little bit more information to help, what year/series is your car?
Is the fuel running out of the tank you are using or from the opposite tank?

Thank for a quick reply. I think it’s a series 2. Fuel runs out of the left tank initially, the one am not using, and then same left tank whichever tank I use.
The canister has a small hole at the bottom, maybe it’s normal to be there. I blew the outermost pipe that goes into the black canister and fuel/air blows out of the left return hose.I can’t seem to go anywhere…

Hi Robin.
Car is march 1977.whichever tank I use, fuel runs out of left side over hose. Initially I ran the car on a submerged pump in a container and I drove up an down almost 120 km, issues were less power, max 60-80 km/hr.
Back to the fuel issue, I can’t seem to find the suggested one way valve if it’s the issue

You can post a photo here of the canister with the hole.
The change over valve is in the boot.


No valve in the boot

can you give us pics of the fuel setup in the boot. pumps etc and the carbs…i see you’re in QLD

Thank you.Yes in qld.
Pump’s not in the boot, but behind rear wheels. Cars are stratsberg or something. Nothing in the boot at all.

ok fuel pumps in the Tanks, carbs are strombergs, can you take a pic of the carby system setup if it has the auto choke system…a wide view…also were the carbs
opened up & cleaned out before starting - fuel filter reverse flushed etc.
i’m in sydney but still can help you out…

the black canister is the fuel evaporative control box, if you have fuel leaking there as well as the overflow hose then the carbs are flooding


Thank you

you can service the carbs - quick clean inside etc - on the manifolds, just remove air cleaner & service one by one, did you find the switch over valve for the tanks?

you can get full info about your carbs (175 CD’s) from my site library - free -
http://www.jaguar-wiring-schematics.info/Stromber%20carbs.htm

Welcome, Henry - read ** for remedial actions and the rest for information…:slight_smile:

The canister is connected to the float bowls, the engine manifold or crankcase ventilation and to the tanks (via fuel separators in the C-pillar) by the three hoses at the canister…

When the engine is not running, vapour is vented to the canister, through the charcoal and into outside air. The charcoal adsorbs fuel vapour - no fuel vapour into the environment…

With the engine running; engine vacuum draws outside air through the charcoal, ‘extracting’ the fuel from the charcoal - to be burnt in the engine…

**Your problems is that the float bowl(s) is (are)
overflowing, as Tom says - either stuck needle
valve(s), sunk float(s) or possibly wrong set float
level(s). One or both carbs may be involved; a carb
overhaul, as Tom also suggests. You may get away
with just cleaning the bowl(s) and changing the
needle valve(s) as required…

As is, the pump is just pumping fuel into the canister, engine and tanks - the pressure relief valve in vent line from the canister is 'T’ed to both tanks. In principle, tank overflow should no happen; a pressure relief valve in the ventline should block it. However, as only one tank overflows - the other tank may be too low to overflow…?

** Do not(!!) run the engine/pumps until carbs are
rectified. The overflow may extend to the separators
in the C-pillars - causing leakage into the cabin. Also,
flooded carbs will in itself grossly overfuel the engine
and the overflowing canister will add to it. Which
explains the poor running - which will also be the
case using an external fuel source…

The charcoal/canister should be replaced; liquid
petrol ruins the special properties of the charcoal

The hole in the canister should not be there, but may be a drain hole - on the ‘open air’ side of the charcoal…

Frank
xj6 85 Sov Europe (UK/NZ)

Thank you Frank,and Tom.Well explained.
Can I clean the bowl(s) and change the
needle valve(s) as required on my own…, or will need a jaguar mechanic to do it? complicated?

Do you know where I can find the fuel return hose? It’s a xj6 4.2liter,1977 model. Does it have any fuel return hose from carburettors? Could it be behind the back seat( none at all in the boot)

It’s uncomplicated in itself, Henry - but access depends a bit on carb types. You may need to replace the needle valves - and reusing gaskets may not be the best option. You also need to verify that the floats are not leaking/containing fuel - and check float levels…

This will eliminate the obvious problem at hand, but there may be other issues with the carbs requiring more remedial actions. Which also is usually a DIY, but require an appropriate rebuild kit. The need for this depends on behaviour after initial ‘clean-up’…

Carbs used are generally not Jaguar specific…

Frank
xj6 85 Sov Europe (UK/NZ)

There isn’t a fuel return hose on Carburettor equiped cars.