At 09:03 PM 11/5/97 -0000, birdy wrote:
>
>>From what you have told us the problem is not with the car running to rich,
>a red hot and glowing catalytic converter is a sign that you are running
>lean. A rich running car will run cooler.
But I have looked at the sparkplugs, and they are a bit sooty. That's the
reason I believe it's running rich. Leaning the needle has decreased (but
not eliminated) the redness of the exhaust just past the catalytic converter.
>
>Your problem may well be due to carb icing. If you are driving around in
>temperatures of 25 degrees fahrenheit (about -3 celcius) then carb icing
>can become a problem. The carb will only be iced up while the fuel is
>flowing through it and then when it stops the ice will melt, leaving
>puddles of fuel in the mouth of the carb. One way to get around the problem
>of icing is to make sure that you have the original airbox attached to the
>carb and that if there is any temperature controlling device within the box
>it is set to the warmer position. The temperature device usually takes the
>form of a flap in the airbox which draws in air from a heatbox on one of
>the exhaust downpipes, this should be open when the car is idling so that
>when there is a weak mixture going through the carb it is a warm weak
>mixture. When the throttle is opened some more the flap reverts to it's
>other position which lets nice cool air from the main tube to give the best
>power (the cooler the air the more power you get).
Car is working as described so far.
>
>Some airboxes have an adjustable tube which can be twisted down towards the
>exhaust manifold during the winter to prevent carb icing.
My airbox intake tube (a flexible aluminum hose) runs from the airbox (air
cleaner in the USA) to a housing on the manifold. All seems to be in order.
>
>If the airbox is set correctly but the problem still persists then this is
>what i suggest.
>
>Set the carb up for normal running as described in the workshop manual (no
>airbox)
Ah-ha! I thought the carb mixture should be set with the airbox and filter
in place. There have been several threads on this List from folks who have
installed (for example) K&N low-restriction filters, which have required
carb adjustments as a result.
Otherwise, I have followed the procedures in the Bentley shop manual and
the Haynes Carb manual.
.>
>Set the flap in the airbox constantly in the hot position so it is drawing
>all it's air through the heatbox on the manifold.
>
>If you suffer power loss then either enlarge the hole for the hot feed or
>reset the flap to it's original position and make sure that the air that
>goes in through both entrances is warmed by the exhaust manifold.
>
>If any of this is not clear then I can draw diagrams. :)
I get it (being intimately famililar with the carb now). But maybe you
should post your diagrams to the List anyway...
Thanks>
>Birdy
Thank YOU.
P.S. New floats arrived in the mail to-day...will be installed soon.
Atwell Haines
'79 Spitfire FM96062 UO
Succasunna, NJ USA
"Q: How do Blonde brain cells die? A: Alone."
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