Conference terri::cars_uk

Do the sidelights work?  They're usually on the same circuit as the tail lights.
If they don't work, check the fuse.  If they do check the tail light fuse
anyway.  Find out what else is on the same circuit and check whether that works.
Check both bulbs are intact.  Try new bulbs anyway.  The wires to the lights
probably come from a common wire, connected somewhere in the boot.  Check all
the connections are secure.  Clean and reconnect even if they look OK; car
electrics are a law unto themselves.

Scott

    
    ..or, it could be like my Land Rover - the lights are scared of the
    dark! -  I keep fixing them, and checking all is ok, and as soon as it
    gets dark and I put them on 'for real' they won't work.......
    
    It is a shaky connection in the indicator stalk - so that every time I
    use the indicators, some of the wires move, and it depends where they
    end up whether or not I have lights! 

    Also,
    
    She is desperately trying to stall on tickover.  It is my guess
    that because the revs are so low, my oil pressure drops lower than
    it has ever done before.  
    
    Am I right????
    Can anyone give me any hints as to how to go about adjusting the
    Idle Screw on the carbs???
    
    Kris.

    
    get hold of a small screwdriver.....locate screw (follow throttle cable
    to end, screw usually underneath)....play away to your heart's content
    
    :-)

    Is it really THAT easy?
    
    Even with twin carbs?  No probs??
    
    Kris.

    
    well, you didn't ask how to balance them, did you ?
    
    that's a bit more complex ;-)

    
    single carbs, it is *that easy*...just don't get it too high, or too
    low...

Twin carbs are a bit more tricky, as ideally you need a special gauge to connect
to both to check they have the same vacuum.  But here's some tips...

With twin SU carbs, there is one throttle cable, connected to a bar which
controls both carbs.  Choke cable similar.  Choke adjustment is via the
fast-idle screw, and if the car starts OK and the choke seems fine don't worry
about that one.  Idle and mixture are the two to look at.

BUT before adjusting the carb, check and adjust plugs, points, timing and (my
favourite) rocker clearance.  If in doubt, buy new points and condenser, and if
there's anything on the plugs that won't come off with a wire brush renew them.
It's a waste of time fiddling with the carbs until you've done all that.

So to the carbs.  Do all this after a few miles so the engine is hot.
At each end of the throttle rod, loosen the screw/bolt that
connects it to the carb, so that you can adjust each carb separately.  Start by
turning both screws the same amount in the same direction (clockwise to increase
revs) until the tickover sounds fine.  Then take the air cleaners off, and
listen to the hiss at each carb inlet.  Now adjsut the screws the same amount in
opposite directions unitl both carbs hiss the same.  Put the air cleaners back
on and repeat the whole process until no more adjustment is needed.

To adjust the mixture, feel under the dashpot assembly for a small pin.  Push
this up until it meets resistance, then push a bit more.  If the revs go up, the
mixture is too rich.  If they go down or it stalls, it's too weak.

To enrich the mixture, turn the large nut under the carburettor (where the
flexible pipe from the float chamber enters the main carb body) anticlockwise as
viewed from below.  To weaken the mixture, turn it clockwise.

Correct mixture is when the revs increase very slightly on pressing the pin.

Adjust the mixture on both carbs, then go back and do the idle again.  Repeat
the whole lot until no further change is needed.

You should be able to do the whole lot in less than an hour, depending on how
much adjustment is necessary.  And it's very satisfying when you pull away and
find all that power you thought was lost...!

Scott.

    Just to reassure you, and endorse -1, I did this on a 1275 Sprite and 
    it's a bang on description. 
    
    Sounds involved, but works well. My only hint (which may seem obvious)
    is to use a small pipe to listen to the hiss of the carb. rather than
    shove your head into the engine bay. (if it wasn't an obvious hint
    i'll go one further and say don't put the pipe in your ear, just hold 
    it close enough to hear the hiss)
    
    Good luck,
    Tony

    There are a number of gadgets - the Unisyn comes to mind - that will
    make balancing easier.  They display relative air flow.
    
    As far as your earlier question about the taillights - the problem is
    simple -
    
    
    	Lucas Electrics!
    
    My guess, from long experience, is a loose or broken bullet connector
    someplace in the system.  Get a voltmeter or a test bulb and trace
    backwards.
    
    	-Barry-
    

Another idea is to get a length of transparent tube and put a dried pea (or
similar) in it.  Then put one end in each carburettor, with the tube hanging in
a loop.  When the pea stays in the middle, the air flows are the same.

As an addendum to .9, don't forget to tighten up the throttle linkage when
you've finished!

Scott

If all that seems like too much trouble, then I would say Beach Hill's MG Spares
and Services are not bad!

I have used them for several years for the two Midgets I have used/rebuilt!

Cheers,

Steve

PS. Scotts description is bang on.  Instead of listening to the sound made by the 
carb, I used a Carb-balancer, which I can loan to you as long as you have a bit 
of tube that will fit it.  I dont have the tube at the moment, as it is used to
connect a full size gas bottle to my little Mig welder.  The Midget doesn't need
tuning at the moment as it hasn't got an engine!!! 8^)

    Hi Kris,
    
    What was the solution for the original problem? (Taillights not
    working)My recently purchased MGBGT (US) has the same problem, but
    it's worse: Brake lights don't work as well.
    
    Regards,
    
    Hans

    We'll the solution was to be found in the fuse-box.  At first I
    was surprised as normally there is one fuse for the left hand side
    lights and one for the right hand side.  I therefore didn't expect
    both not to work at the same time.  
    
    It seems, however, that someone had been fiddling with the electrics
    before I bought the car and both lights were on the same fuse as
    well as the horn and the interior was.
    
    Anyway, the problem (I hope) was just dirty connectors in and around
    the fuse box.

    Being that the MGB only has about three or four fuses, I suspect that
    there has to be a lot of things on each fuse. One fuse for each side
    of the car must be a new idea. I must admit I've never seen it on any
    oldish British car.

    Dirty contacts is a common problem with this type of Lucas fuse box.

  Mark

    Gotcha!
    
    Kris, My 71 Gt had the very same problem!
    Now the wipers & interior blower. The share the same circuit....
    
    Hans

    Please put all future MGB releated material in note 1266. 
    
    This topic will be write locked
    
    Richard (co-moderator)