AW: AW: [mg-tabc] Re:colortune

[Paroor]

Dear all,
Need some advise about TC SU carburettors. David Tasa and me
cleaned TC448 carburettor and replaced the 2x2 Cork washers against rubber
gland washers and the 2 big cork packing washers against new ones. Every
thing set according to specification.

When the ignition/SU pump is switched on, the front carburettor started
flooding. Since the air cleaners are removed, the flooding can easily noted.

After running for few minutes removed the both float chamber lid. The
front flooded carburettor float was touching the bottom of the float
chamber. The rear carburettor float was floating at correct level.

Set the needle liver of the float according to the specification and started
the engine again. The slow running is so bad as if the engine is so rich in
fuel, that it can only run at higher RPM. While running if the second spark
plug connection is removed there is no influence to the engine running
character. The carburettor is fitted with a M5 needle and jet.

If the float needle is stuck or not operating properly what is the symptom ?
Or is it some thing wrong in the assembly of the front carburettor. New
Grosse jet is ordered. But it will take time to get it.

There are some t-abc members experienced such carburettor problems. Can any
body help me ?

Thank you

Madhu

-----Urspr ngliche Nachricht-----
Von: Chip Hellie [mailto:chiphelli@yahoo.com]
Gesendet: Montag, 21. Juni 2004 10:15

Gene,
I'm not sure what you're asking exactly, but I can
tell you how I(a backyard mechanic)tune dual SU carbs.
They are such simple devices and it cracks me up when
people seem to think they are such mysterious
creatures! I think it's extra funny when people toss
them out and put on some other type such as dual
downdraft Weber set-ups which really are complicated
when compared with a SU which only has two moving
parts.

First,make sure the throttle butterflys open at the
same time. Warm up the engine, then when it idles
check to make sure they're balanced. I use a UNI-SYN
gauge. Place over the throat and see where the float
ball sits and make sure they both are the same.

Most people never think about this one, but I have TWO
Uni-syn gauges, and once both carbs are balanced at
idle, I put a gauge on both carbs, get my cute
girlfriend to press on the throttle pedal, and I make
sure both carbs respond exactly at the same time. This
is where most people screw up. Even if the carbs are
perfectly balanced, if the rear carb comes on way
before the front, it isn't gonna run for s*#@t.

When this is all set correctly (not rocket science,
just a lot of fiddeling about) then set the mixture.

Most SU's have a button on the side you push up, which
lifts the piston. Use them! If they are not there,
then raise them with a small screw driver, not your
fat thumb! Were talking about 3/16".

Pick your favorite carb, raise the button and listen
to what happens.
It should raise the idle slightly for a second and
then the rpm will drop and the engine will start
shaking like Jerry Lee Lewis. Perfect!

Raise the button, and if the engine picks up speed and
stays there, then you're too rich (screw the jet nut
up,in, clockwise, your preference).

Push the button up and the engine just stumbles and
shakes, maybe dies, then it's lean, so get the jet
down,out, anti-clockwise.

Proceed to the other carb and then you're finished.
Takes 20 mins. tops, and it's free, other than your
time.

This is all you need to know to tune them, provided
the carbs aren't worn, floats set right, and don't
forget that little squirt of oil in the damper.
That'll be $5.00 Sir..
Chip Hellie

--- Gene Wescott wrote:

> I need to tune carbs on my 47 TC, and am daunted by
> having to remove the
> intake manifold and all the connections to get at
> the bare carbs. Mike
> Goodman could set them up by taking one out by
> raising one piston at a time,
> and hearing how the engine ran, or stopped on just
> one carb. I never
> mastered that technique, but I would appreciate an
> explanation and how to do
> it. Otherwise, years ago I bought a colortune set,
> but never had much luck
> trying to judge what the color was. I thought I
> might try it again on
> cylinders one and four without removing anything,
> except balancing the carbs
> air inflow. Comments and suggestions please.
> Gene Wescott

[D&J Edgar]

> The
> front flooded carburettor float was touching the bottom of the float
> chamber. The rear carburettor float was floating at correct level.

Here lies your problem. Front float is sunk and is not shutting off carb
float needle valve. Fuel just keeps pumping in and flooding. Look for a
pinhole leak in the float. You can try soldering shut but it is tricky.

David Edgar, TC 5108
El Cajon, California

[Paroor]

Hi Ray,
As per your advise I took the float and put it in the hot water. The
metal float body get heated air bubble will come out so that one can locate
the hole in the float if any. In this case the float is in good shape. I
exchanged the float against the other carburettor float. There was no change
in running character of XPAG. When I exchanged the cover with the float
needle get the problem is over. But the other carburettor got the problem
now. So I suspect that the needle jet is getting stuck influencing the fuel
flow. I will install a in line paper fuel filter. Then had to try fix
another float needle jet.
Now I got a little bit of bad conscience. A fuel pipes are still the old
ones. I cleaned it the longer copper pipe. Butt he shorter one was not clean
enough may be ? The tank is clean. The thank is sand blasted sealed with
fuel resistant paint. The bottom part is replaced against new metal sheet.
So Tank is better than new.

Theory is one knows every thing. Nothing works.
Practise is every thing works, one wonders why ?

Thanks for the support.

Madhu



-----Urspr ngliche Nachricht-----
Von: mg-tabc@yahoogroups.com [mailto:mg-tabc@yahoogroups.com]Im Auftrag
von 1939mgtb
Gesendet: Mittwoch, 31. August 2005 19:59


Madhu,

If the float is sunk to the bottom of the bowl and gas is running out the
top, the float is faulty. Either solder it up, or buy another; the second
is the best choice.
If the needle sticks and the engine runs super-rich, sometimes a rap on the
top of the carb with a small wrench or screwdriver handle will let the trash
pass through and the needle to seat.
The factory manuals recommend you merely push down on the tickler and let
incoming fuel wash it out.

Best,
Ray
"Spes mea in Deo est"

[Paroor]

Dear All,
I am getting closer to the point. The float is not defect. In TC
0448 the two flat chamber lids are different. The rear one got a pin to
press down the float and got a solid liver operating the float valve. The
front one do not have this pin and the liver operating the float looks
entirely different. I am sure this front problem carburettor was fiddled by
PO several times.

I tried to get a new grosser Jet. But it is not readily available.
Yesterday I run the engine for a short while after replacing the float
valve. Now the both float chamber is marinating almost the same fuel level.
So I will check the fuel level today morning.

As Terry advised I checked the float liver, it is getting stuck. The liver
had to have a little tab restricting the liver going too far down. This is
not set proper. If the float is empty the liver goes down too much letting
the needle slip out. So it get stuck. So the flooding the carburettor is the
result.

The car is starting at the very fist turn. So I did not fiddle with the
ignition timing. I thought it is better do set it proper after fixing the
carburettors and slow running. I also do not trust the new Champion spark
plugs.

Thank you all once again.

Madhu

[Paroor]

Hi Terry,
Your mail came few hours late. I went to the local shop today
afternoon, got an exchange lid with tickler so that both look alike. TC 448
had two lids with connections on the left side. I never noticed it. Now I
got a right connection to for the front carburettor with pre set valve. I
fixed the lid to the carburettor and and tuned the switch and pulled the
starter. Like a wonder all the four cylinders are working with the same
power. The trouble was only with the sticking float valve. I also got new
over flow pipes. But as you said it is of no use combining this pipe with
tickler.

I will keep the ticklers at present but may fill the bottom with epoxy`d
soon. The oil sump leak is also fixed. Now I can do all the fine tuning of
engine and finish the wiring.

Thank God. Thanks to all members who came with an advise.

Madhu

-----Urspr ngliche Nachricht-----
Von: Terry Sanders [mailto:taterry@pacbell.net]
Gesendet: Freitag, 2. September 2005 15:40
An: Paroor
Betreff: Re: AW: [mg-tabc] Re:colortune


Madhu, another caution, get rid of that tickler pin on the one float
chamber. Find another one like the one with no tickler. The problem is
that if the float bowl floods, the petrol will flow out of the tickler and
not the overflow perhaps causing a fire. We lost one TC to this cause. The
tickler can also be epoxy'd shut or a very small oring added to it to make
sure petrol does not flow up through the tickler. Having a tickler is not
worth the danger of a fire.
Terry



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