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Re: Midget still running too rich

To: Jeffrey Lo <Jeffrey_Lo@ccm.hf.intel.com>
Subject: Re: Midget still running too rich
From: paisley@cme.nist.gov (Scotty Paisley)
Date: Mon, 20 Apr 92 23:24:20 EDT
Jeffrey Lo writes:
 > > Some background:  1979 MG Midget - single Z-S carb.
 > > I've had the carb and choke apart numerous times and everything seems
 > > -to be
 > > OK there (although I freely admit I'm far from an expert on these
 > > -things).

In case no one else mentioned it, do you carbs have the removable
needle in the jet?  If so you can lean 'em up by rotating the "special
tool" to the left.  That will lower the needle into the jet to lean it
up a bit.  Hey, what a great way to remember.  Lefty = Leany, and
Righty = Richy!  I did that on my TR6 carbs (ZS 175s) and it helped...
I've heard that most ZS's run rich...  Mine are runnig lean right now,
but I have an air leak somewhere.

 > Well, as I think someone on the list mentioned a while back, there is a piece 
 >of
 > the Z-S 175CD carb. called a temperature compensator or something like that 
 > (I'll have to check the book).  It's a plastic and metal device about 2-1/2 
 > inches by 1/2 inch on the side of the carb.  Anyway, the Haynes Z-S manual 
 >says 
 > to never touch the screw settings inside the thing or it won't work right.  

Tis true!  I screwed with mine, and my idle never was the same,
until... I took the temp compensator off (car warm, but not hot) and
gently seated the plunger thing in there.  Basically I think that as
the car heats up, this sucker lets more air into the intake.
Therefore, if this guy is your problem then I would take it off the
carb with the car cold, and seat it ever so gently (with a tiny
socket) and see if it will open up to let it run leaner.  You might
even want to have it open just a hair.  What the hell, it's running
rich, what do you have to loose?  Get some air in there!  What fun!

-Scott


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