Manuel Choke Conversion on xj6 series 2 not working

Good Morning all,
I need help with my Manuel Choke Conversion.
When i Pull the choke cable it operates the Conversion device but it appears not to operate the fuel feed to the carbs as the engine cuts out after starting and when i place it into gear. There is no increase in revs so can only assume the fuel is not being sent through to the carbs to initiate a cold start. Once the engine is warm i have no trouble what so ever. with it. Does anybody know the problem and the way i can solve this please?
Series 2 XJ6 Convertible

A mixed bag. Nomenclature issue to begin with.

To many of us, me included, the “choke” function means that the amount of air to the cylinders is reduced, and the fuel not so or even enriched.,

So, is the device a manual enrichment device?
Or a device to reduce the intake of air?

Figure out which function. then see why it does not work…


This will be the AED which has been converted from automatic to a manual enrichment device. First off can you confirm that the unit is receiving fuel?

The device works by rotating two small cam lobes which operate two tappets: one fuel, one air. Check that the cam lobes are not slipping in their shaft. You may have to remove the upper frame from the unit to check and reset the mechanism. Paul

With no increase in rpms the ‘choke’ does not pass air through the devise for enhanced cold idle, Colin - fuel variations do not alter rpms…

With insufficient high idle, some 400 rpms above hot set idle, the cold engine drag may stall the engine in gear. With the AED conversion; idle must increase when choke is pulled as air is added…

Principally; as choke is pulled one cam fattens fuel, the other adds air - the cams mechanically perform the internal functions of the AED. A likely cause is a clogged hot air pick up unit restricting air flow to the AED. Clean it…

xj6 85 Sov Europe (UK/NZ)

Thank you Frank

I have taken the device apart to inspect it before . Is the Air intake the one with the spring ?


The hot air pick-up heats air as it passes through the device, Colin - clamped to the exhaust manifold…

It should have no restrictions inside; the air flow is controlled in the ASD - whether modified or not. In the original ASD configuration; the hot air flows through the ASD, affecting a bimetallic spring that gradually closes the air flow as the engine heats up. In the modified version this is done by one of the cams…

As far as I know, there is no other air passage to give enhanced cold idle when the AD is used…

xj6 85 Sov Europe (UK/NZ)

Thank you Frank .

I will investigate.



some time ago I posted the instructions for the installation of the manual operation conversion kit. They document the position of the cams as well as the size of the gaps between the pistons and the cams. You’ll find it with the search function.

There is no point in trial and error here. You just have to get it right. Yet, to assure the starting point of fault finding, you’ll have to make sure that with the choke cable fully pushed in both cams do not depress the pistons.

Good luck

75 XJ6L 4.2 auto (UK spec)

Thank you jochen I will use the search tool

Morning Jochen

I have used the search function but have not found the thread. Can u tell me the title of the thread please.


Here Colin, just googled “AED manual choke conversion instructions” - found on SC Parts site. I bought mine from SC Parts some time ago, works really well. Jochen is correct - the clearances are small and everthing must be done carefully - I had to shorten up (by grinding) one of my tappets to get correct clearance - detailed in instructions. Paul

Thanks Paul that’s very useful