I originally sent this to the MG BBS but got no response - I
guess I must have stumped them!
Anyway, I have recently made the conversion from the ZS to the
dual SUs. This is the second conversion I have completed. The
first was on my 77 last winter and that went off without too much
trouble. However, the 76 is giving me tons of trouble and I need
some help. One problem (symptom) is fuel leaking out of the
throat of the front carb (not running - ignition on). It seems as
if the fuel pump is providing too much pressure (although there
is no gas coming from the overflow). The carbs were rebuilt prior
to installation and the float needles seem OK. I have also
switched carbs from the 77 and the 76, to test if it was the
carbs, and still get the fuel leaking out of the throat of the
front carb. I also added a fuel regulator which, when set to 1.5
psi, seems to stop the fuel leak but then the car will not start.
Other symptoms included a rough running engine - like it was
missing on one cylinder - which then converted to an engine
running like it was fuel starved. Also, intermittent periods of
black smoke out of the exhaust and fast idle.
I know, Iknow _ it's all over the place. I'm not sure if I'm
dealing with a bunch of small problems, one big problem,
coincidence, bad karma or some combination of these! I need help
sorting this out!!
Some questions:
Does the 76 have a high pressure fuel pump compared to the low
pressure systems in earlier cars?
Any ideas concerning why fuel is leaking from the throat of the
front carb - much less why this would happen on two different
rebuilt sets of carbs?
I can believe that overly lean or rich gyrations may be related
to the fuel leaking out of the front carb and if so then there is
a bigger problem but what is it?
Is there something simple here I've overlooked?
Thanks in advance,
BTW, had my first car fire. The C started smoking and then
flaming out of the cowl where the indicator switch is located.
That was a hairy driving experience - have not assessed the
damage yet but assume that there is some significant electrical
problem.
Dr. Doug
|