Bill,
Not a black art, but it does require consistency.
This should be done at highway speeds and 5 miles is plenty of time to
establish a tuning condition. Find a deserted or low traffic area, run to
4-5 miles, shut off ignition and coast to a stop then read plugs, check 1 &
4 if running dual carbs (minimum-all 4 is better as it will show individual
cylinder conditions)
I am assuming that you are running SU's given the year of your Sprite. The
factory has done a BUNCH of testing to select the proper needles for that
cars best multi-condition operation. You can spend many many hours and a lot
of money trying different needles, unless you are racing stick with the
factory recommendations.
Regarding your symptom...1st check the compression, if ok then check the
ignition, esp. points and the advance mechanisms. Set plug gap to .025 and
check that they are all firing equally, a 40,000 volt "sport" coil will at
best give you bragging rights but not enough to arbitrarily change the plug
gap. If all is well there we'll assure that the carb pistons are topped off
with oil. Assure that the springs fitted are correct..( the oil and the
springs act in concert to keep the mixture on the rich side under
acceleration). To make a gross check, one might remove the springs
altogether and check plug color...it should go rich. Assure that the needle
does not bind in the jet bore throughout it's entire travel and assure that
the jet is not ovalized from previous misalignment. Assure that the float
bowl fuel level is as specified.
If not ok yet, go back and do what ever you decided to delete because you
were sure it was ok.
Dave@SWCP.com Taos Garage Annex in Albuquerque
'59 AH :{) '54 100
http://www.britishcarforum.com/TaosAnnex.htm
----- Original Message -----
From "Bill L" <pythias at pacifier.com>
To: "Spridgets" <Spridgets@autox.team.net>
Sent: Friday, November 01, 2002 3:55 PM
Subject: carb tuning----plug reading.
> Hello Spridgets,
>
> ok, i've been convinced of the utility and/or futility of using
> a color-tune. i can see that once the job has been done, the
> tool would most likely be left in the drawer thereafter soooo
>
> i've decided to try it using a carb-sync and "reading" the
> plugs. now, the question-------
>
> how long does an engine need to run on a "new" setting of the
> carbs before the PLUGS change color? 10 minutes? 10 miles? one
> tank of gas? clue me in ?! i'm trying to get rid of a "stutter",
> that is the car stumbles (after it is fully warmed up) as i
> accelerate, especially uphill, or around a corner to the left.
> not so sure about a corner to the right.
>
> --
> Best regards,
> Bill mailto:pythias@pacifier.com
> '66 Sprite
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