In <199607011808.NAA05633@dynacomm.fse.com>, Bob Dallas wrote:
>Okay, I tried to follow the directions carefully and even had my warm beer
>to prove it, but I need help. These carbs are on a TD which hasn't been run
>in 25 years. I have cleaned them up and put in the Moss rebuild kits and the
>motor runs good but I think a lot rich. The car continued to run
>rich---I would raise the piston 1/16 of an inch and the motor would
>speed up and continue to run at that speed. I need your advice.
>
>Does the tightning of the adjustment nut makes the carbs run leaner??? Could
>it be that these carbs need more than a rebuild kit--maybe new needles?
>Other Ideas?
>
Tightening the nuts causes the jets to rise, yielding leaner
operation. The "lift-the-piston" tuning trick is generally a very
good (and sensitive) way of setting SU's _providing_ all else is well.
There are two common problems with these carbies. (1) The jets can be
worn oval due to improper centering. This also destroys the needle.
You may be able to center the pot such that you get no needle drag,
but this doesn't mean that it hasn't happened earlier. This will
abrade the brass of both the jet and the needle. You can't really see
the damage easily. Jet and needle replacement is in order for carbies
of unknown history. Worn jet and needle will yield rich running for
any setting. (2) All H series carbies have bad problems with
throttle shaft wear. If you can feel _any_ lateral slop of your
throttle shafts (often hidden by return spring tension) you cannot get
the carbs to work properly. Another test is to spray some ether
(starting stuff) or carb cleaner around the throttle shaft bearings
while the motor is running and listen for changes in speed. I
reiterate that you will never get the carbs set right with loose
shafts. A number of shops (e.g. Apple Hydraulic) can rebush your
carbs for a reasonable fee.
A. B. Bonds
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