Technical Questions

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Q & A - Previous Submissions

March 30th 2015 - Triumph TR 6 1973

Q - I have 2 SU carbs on my upgraded engine, and the choke cable only to one carb.  If I don't start the car for 2 weeks, it takes about 60 seconds to fire on only one cylinder.  Then it catches on a second cylinder.   Finally, all 6 are firing.  The engine shakes violently while it is firing on less than 6. This is not good.  Should I disconnect spark plugs and crank it for 60 seconds or so?


A - There should be a linkage connecting the two choke levers, so that one cable will pull the choke on for both carburettors on the S.U.'s (different from the Strombergs). If it's not fitted, installing one should get both chokes operational simultaneously. If there is one, it's possible that the linkage needs to be adjusted to properly synchronize the chokes. I'd suggest starting there - once the chokes are operating properly it should start relatively smoothly, although they'll always have a somewhat extended cranking time after being parked for any length of time.

With no accelerator pumps in the S.U. carbs, they really do need properly functioning
 chokes to start up properly. It's also important to make sure that the throttle plates 
and mixtures are balanced properly, as this will also cause uneven running between 
cylinders, more obvious when trying to start from cold.
(This all assumes that the ignition system is in proper working order, of course).

April 1st 2015 - Jaguar S Type 4.2 2007

Q - The headlights on main beam are fine.  On dip beam, they only illuminate the road just in front of the car.  Is there an adjustment to raise the dip beam to a more practical level?


A -  Depending on which lamps are fitted to your car:

If they are HID lamps, the car will be fitted with an automatic levelling mechanism.  If this is the case, and they are not levelling, it can be a broken link on the lamp motors or an electrical fault in the wiring/module, etc.

If they are the standard Halogen lamps, there is a manual adjustment.  Frequently the adjusters get broken - they are a bit of a weak point - causing the lamps to droop. There are some aftermarket kits available to repair them if this is the case - I believe it is still part of the headlamp assembly if purchased from Jaguar.

Also, make sure the bulbs have been fitted properly - I've seen them not fitted properly into the sockets which will cause poor illumination.