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Re: SU vs Weber

Subject: Re: SU vs Weber
From: "A. B. Bonds" <>
Date: 10 May 1995 10:15:41 -0500
In <>, Jay Tilton wrote:
> (MR JOHN H TWIST) writes:
>>It is my
>>experience that the charts provided with the colourtune tool demand a BLUE
>>flame, when, in fact, the MG idles best with an ORANGE flame.  I do not use
>>the colourtune myself, and have experiemented with it only twice -- but
>>those were my findings.  GO FOR THE RED!!  John Twist

>While I can't convincingly argue with the experience of a seasoned pro, and 
>I'm not trying to start a "flame" war (Bwahahaha!  I kill me!)

No, I kill you.  BANG.

>So, with a yellow flame you're throwing too much fuel in.  The only time I 
>can think that you'd want a rich mixture is during acceleration.  Sure, a 
>rich idle mixture will probably idle smoothly, but I worry about plugs 
>quickly fouling with carbon, not to mention wasted fuel.  Also, those 
>subject to emissions testing will most likely fail due to high HC content if 
>you don't dial in a lean mixture beforehand.
>Probably what you really want would be a just-barely-out-of-the-yellow flame.

Yeah, I messed with this for quite some time.  The Colortune
instructions imply that you ought to start with a yellow, then move
barely blue.  What actually happened was that I set the idle mixture
up for minimal "pinking" (I looove British colours) by ear first.  The
correct point was fairly well-defined (within about half a turn).
Later I threw on the Colortune and found blue.  I backed off on the
screw (enriching the mixture) and it immediately turned yellowish, so
I most probably had hit the barely blue point by keenly honed
automotive sensibilities, or blind coincidence.  I certainly won't
argue with John, who is clearly wiser in these ways, but might suggest
that maybe things are a bit different with a Weber instead of SU's
(yeah, I know, gas is gas is gas).
 A. B. "Messing with my carb is the only way I'm gonna get rich" Bonds

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