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Jaguar Repair/water choke zs cd175 1977 xj6L


Deposits on a brass screw on the bottom of the choke indicate a fuel leak.
Pics online of 78 Midget water choke refer to this as the end of the housing for the brass breather and enrichment needle.
On the Midget ZS this housing ends in blank plug.
On my choke there is a brass screw and washer that seem to secure a rubber washer.
Could this site actually be the source of a fuel leak?
Can I just unscrew the screw and washer and replace the washer to fix any suspected leak at this site?
Will removing the screw misadjust anything?
Thank you

ANSWER: Hi David,

Could you take a photo of this brass screw on your choke assembly so I can ID it. There are several different types of choke assemblies used on Stromberg carburetors but all of them have their passageways and ports above the float level so it would not be a common source of a fuel leak. And none of them have any adjustment screws other then external linkage adjustments. Also take a photo of where you note fuel leakage.


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brass screw
brass screw  
QUESTION: Picture suspected leak water choke cd175

ANSWER: Hi David,

I believe there was suppose to be a "Freeze Plug" type plate covering that screw and it has fallen out. That screw you see is the end of a piston and seal. That plate was not suppose to come out at all. Not sure you can even buy that plate. You may need to make one and seal and peen it in. Or buy a complete choke assembly. Another option would be to find a British car specialist in your area and get a used choke assembly or check on Moss Motors for a conversion to a manual choke. But I doubt that has anything to do with fuel leaking. You need to remove the float chamber and check that large plastic plug in the bottom of the float chamber. It has a rubber "O" ring that is noted for leaking.


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Both carbs are missing this plug.
Moss has an application for MG which is the same diameter but no specific part number for Jag.
The car seems to run fine without them.
What is their function and are they necessary?
Thank you,

I am not sure on that model but I think it is a vacuum cylinder. And my guess is that the car had a backfire in the intake and it blew the plugs out. To be sure you should pull one choke assembly off and check the passageways to see if that is correct.


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Howard M. Fitzcharles III


Jaguar from the XK 120 to XJ-6 ser. 3 1987


Dealership line mechanic on MG, Triumph, Jaguar for 15 years, Instructor in commercial mechanics school 2 yr. Product information manager for piston and valve manufacture, Instructor & hotline answer man for import car parts importer 15 yrs.

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