Now 
why i see a leak[fuel] under this part…
The fuel leak is supposed to come out through the carb bowls through the two small pipes (drain) to the ground…but I had not seen a gas leak here…what should I do or why is that leak? there…???
I didn’t know there should be a gas drain to the ground.
You don’t mention which model, so I’ll speak from my past experience with my S type. Other models will be similar.
This is the drainage point for the plenum chamber. There are two and they should have flexible tubes that run down through a clip fixed near the oil filter. It is not unusual for this to occur when a float bowl is flooding and overtops the jet bridge. This is the first level to overflow, not the cap. You will need to check the float and shut off system. Sometimes a float needle can be jammed down if the hinging parts are not freely moving.
jaguar mk2 1967 3.4 LHD…
When one of mine dripped, I realised it was missing the drain tubes, but the clip was there. I cut and fitted two pvc tubes to suit.
That’s what I’m going to do, buy and put those two little lines…and fix that problem.
Make them long enough to almost go to the ground. Fuel grade hose.
Well, yes and no, You really need to determine the root cause of why there is any fuel in the plenum. If all is right, there should be none.
I think fuel in the plenum would be caused by blow by from the makeshift PVC orifice at the front of the engine which goes to the base of the plenum to be re burned. Over time it could build up to a noticeable amount. Those nipples should have hoses which always fall off and usually interfere with the throttle linkages. I had a poor connection on that tube and the fumes were noticable while driving. I may have too much blow by??
I already checked the 2 (deposit)carbs I think they are fine…if there was an overflow it would have to come out through the drain lines…and fuel is still dripping from under the plenum (through the nipple)…
Any suggestions or if anyone had a similar experience… I would thank you in advance… I don’t want to move the plenum either, it would be getting into more problems…
Ok…so i have to remove the plenum??
No need to do that. Take off the air cleaner and with a rag clean out any gunk that may be inside the plenum. It would be normal to get a dirty rag if this has never been cleaned before. It was a very archaic way in which Jaguar began the process of better emissions. Notice the pipe from the front of the engine to the plenum carries blow back to be reused in the carbs. Fuel coming out of those nipples is a mystery to me and would be answered by others more versed than myself.
When mine was dripping, I removed the plenum and could see that the fuel was slowly dribbling over the jet bridge, indicating the fuel in the bowl was too high. I found that the shut-off needle valve was not able to seal and had to be changed.
That bowl level was really high!! Is this part what they call a “grosse jet”.?? Is so, not a hard fix at all.
You are absolutely right…the car has been sitting since 1992 without maintenance…I have already replaced several parts…I have never had a Jaguar of this age…so I don’t know much about this car…I’m going to clean it without removing the plenum and seeing if it stops the leak… I already checked the needles of the tanks and I think they are fine because they do not leak gasoline through the lines towards the ground.
If the leak continues, it is possible that the reason for the leak is that the seal of the valve is broken…???
As an add on, if fuel if coming up out of the bowls and going into the plenum, can you install a fuel pump pressure gauge. You may not have overflow when the car is static, but once the pump kicks on you could be overwhelming the floats and needles. I have a gauge right after my fuel pump and a filter BEFORE the fuel pump.
As an add on, if fuel if coming up out of the bowls and going into the plenum, can you install a fuel pump pressure gauge. You may not have overflow when the car is static, but once the pump kicks on you could be overwhelming the floats and needles. I have a gauge right after my fuel pump and a filter BEFORE the fuel pump.
Im thinking about.
Thanks so much …
Jaguar fuel pressure is low, below 5psi. You can always install an in line regulator. Facet/perolator makes a perfect pump for us:
Something like this will work temporarily and then you can use it as a emergency
Add images
Huge URL link, should work, Otherwise Google low pressure fuel pumps
Gerard
