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Re: Carb mismatch?

To: Tom Zuchowski <tzuchow@ibm.net>
Subject: Re: Carb mismatch?
From: Ulix Goettsch <ulix@u.washington.edu>
Date: Sun, 16 May 1999 11:36:23 -0700 (PDT)
Cc: Spridgets <spridgets@autox.team.net>
In-reply-to: <001d01be9f9c$b2679540$982c6420@default>
Reply-to: Ulix Goettsch <ulix@u.washington.edu>
Sender: owner-spridgets@autox.team.net
Tom,
you don't mention having synchronized the flow of the cabs with a Unisyn
and having made sure that the throttle plates start opening at the same
time.  Could that be it?

Other than that, you could check:

* the position of the throttle plates when supposedly closed
* when you lift each piston with the pin does it fall back down freely
with a clunk?
* do you have fixed needles?  Are they the same?  Are they the correct
ones? Are they mounted in teh piston correctly?
* Are the springs present inside the "dome"?
* have you tried setting both carbs the same to start with, i.e. both
mixture jets down 2 turns?

Ulix


On Sun, 16 May 1999, Tom Zuchowski wrote:


> Once again, I turn to the all-knowing wisdom of the List. . .
> 
> I was doing some tune-up of my 1275 yesterday. The carbs have always been a
> little odd, but I think they are getting worse:
> 
> 1) With the idle screws backed all the way out, it idles at about 1200 RPM.
> I run them in a quarter-turn so they won't fall out, and that runs the idle
> up to about 1500 RPM. It's a nice smooth idle, although it's so high.
> 
> 2) There is no mixture adjustment on the front carb that won't result in an
> immediate drop in RPM when I lift the slide with the button. The plugs look
> pretty good, though. I've tried hitting the gaskets with WD40 and don't
> notice any change. The float height appears to be within specs.
> 
> 3) On the other hand, the back carb is pretty close to right when the
> mixture nut is run ALL the way up.
> 
> 4) Using the colortune system, I think I have the back carb real close, but
> I don't really know where I am on the front carb since I can run the mixture
> nut down 3 or 4 turns and not really see a color or slide-lift difference.
> 
> 5) The front carb has a plastic float and the back one has a brass float.
> Should I get matched floats?
> 
> I'm guessing that something isn't quite right with each of the carbs. I
> rebuilt them last year after a 9-year sit in the garage without running, and
> either I did something wrong or else there is something loose or gummed up
> that I missed, perhaps. The car starts well and runs well, although it has a
> real tendency to run-on after switch-off.
> 
> I would be most grateful for any helpful hints. Thanks!!!
> 
> Tom Zuchowski
> Clemmons, NC
> 
> 

    Ulix                                       __/__,__      ___/__|__  
..............................................(_o____o_)....<_O_____O_/...
                                              '67 Sprite     '74 X1/9


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