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Strong fuel smell

Jim Latoff
Nation s Capital Jaguar Owners Club *

forum user since 2011-06-17

 



Howdy,

I sensed a very strong odor of fuel while driving and parked. Looking for the leak I found fuel pooled on the thermostat body of the aux carburetor (choke). I also found a unattached vacuum hose between the rear carb and the battery area.

Advise would be much appreciated.

Jim

Strong fuel smell

Jim Latoff
Nation s Capital Jaguar Owners Club *

forum user since 2011-06-17

 

I noticed that the choke assembly is connected to the manifold by one 1/2 pipe. I do not see a separate fuel supply to the assembly.

I understand these choke assemblies are problematic. If I cap the pipe mentioned above then have I isolated the assembly from fuel and vacuumed ? I really don't like the smell of gas and my wife refuses to ride in the car with the smell.

If so does this mean that I will have to keep the gas pedal depressed a bit when starting to run rich, like I used to do when starting my Austin ?

Jim

Strong fuel smell

George Camp
Jaguar Society of South Carolina *

forum user since 2002-11-24

 

Jim the 1/2 pipe is the manifold lead. The AED is supplied by the carb it is attached to. If you make repairs to the area the smell will be gone. I suggest a proper repair rather than a "plug" the holes approach. JCNA offers a very good SU carb pamplet in the shoppe but your shop manual also covers this.

JCRC SE
JCNA VP

Re.: Strong fuel smell

Jim Latoff
Nation s Capital Jaguar Owners Club *

forum user since 2011-06-17

 

Edited on 2012-05-14 9:15:40

Edited on 2012-05-14 9:14:58

George,

Yep, the manual does cover it.

The only adjustment is setting the height of the needle valve.

The selnoid and the theromostate seem to work fine because when I start it cold it kicks on.

I hear the vacume sound coming from the AED.

Then once warmed up the sound goes away and the idle goes down.

I guess I could adjust it so that it is not running as rich by turning the adjustment clockwise
so that the needle valve spring will place more force on the needle leading to less movement and less gas/air ?? I guess that would address the theromostate body filling with gas ?

Or is the carb providing the fuel running too rich and providing too much fuel to the AED ? If that is so then I need to lean out the carb right ?



Jim

Re.: Strong fuel smell

George Camp
Jaguar Society of South Carolina *

forum user since 2002-11-24

 

Jim there might well be no issue with the choke body. If you have a float issue in the feeding carb that could do it. You had posted that you had a vac. line loose which was prob. your brake booster--that being off would upset the manifold quite a bit. My suggestion was to carefully go through a carb tuning and inspection on both carbs. Once that is right then worry with the AED. Alone they give little problem-they normally work or not but unless they stick (the valve) a fuel issue is not often seen.

JCRC SE
JCNA VP

Re.: Strong fuel smell

Bob Grossman
Rocky Mountain Jaguar Club *

forum user since 2004-11-06

 

Jim, don't set the choke needle too lean. The system on the Mk2 is not backfire protected and on cold start, a lean mixture will cause a backfire and it will blow fuel back into the starter carb and you will experience the two drillings on either side of the body to fill with fuel and cause a lingering fuel smell. Best so simply tolerate the rich cold start mixture than to have cold start backfires.
Bob Grossman

XK120 FHC
XK140 DHC
Mk2 competition
S1E - coupe
C-replica

Re.: Strong fuel smell

Jim Latoff
Nation s Capital Jaguar Owners Club *

forum user since 2011-06-17

 

Edited on 2012-05-15 14:22:14

Edited on 2012-05-15 14:20:41

Thanks Bob for the advise !

I cleaned out the theromostat housing with some carb cleaner and backed off the adjustment screw by 1 full turn. I also crimped the female connector on the wire connected to the sensor in the manifold. It seemed loose.

Started it up and the AED came on (big sucking sound). It heated up and turned off. I took it out for a test drive to get it up to operating temp. So far no smell of fuel !



Jim

Re.: Strong fuel smell

Dick Maury
North Georgia Jaguar Club *

forum user since 2006-09-17

 

Backing off the adjustment screw on the Aux carb richens the mixture for what it is worth. As long as the fix worked, that is great.

Dick Maury, Rebuild Department, Coventry West, JCNA President

Re.: Strong fuel smell

Jim Latoff
Nation s Capital Jaguar Owners Club *

forum user since 2011-06-17

 

Thanks !

I checked the manual ..anti-clockwise rotation of the stop screw will raise the needle and therefore the mixture strength..

I have included a photo of the AES unit.

Jim


Re.: Strong fuel smell

Jim Latoff
Nation s Capital Jaguar Owners Club *

forum user since 2011-06-17

 

Here is a pic of the vac hose I found between the battery and the carbs. Any suggestions as to
where it suppose to go would be much appreciated. The hose to the brake boost is intact (thanks for the suggestion George).



Jim


Re.: Strong fuel smell

George Camp
Jaguar Society of South Carolina *

forum user since 2002-11-24

 

Jim in that area of a MK2 there is a battery drain tube and two tubes that drain excess fuel from the bottom of the intake to the carbs. Try checking those. That looks more like a battery drain but it could be a replacement for the fuel drains.

JCRC SE
JCNA VP


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