[NoVa-Corvairs] tech question

Wed Jun 20 22:02:16 EDT 2007

Daniel,

Are you sure you are comparing primary to primary and not one primary to
one secondary?

When you cover each primary with your hand, what happens...should almost
die when you each side.   If covering a carb on the left side does not have
a big effect, than maybe it is a vacuum leak.  Sort of sounds like junk in
your idle circuit though.  I assume that you are doing this with the engine
warmed up and the choke off, right?   You may also want to unplug the
vacuum advance and plug the hose to take that out of the picture as well.

If they are closed properly, then covering each secondary should have no
effect.   If covering a secondary carb effects idle than it is not closing
fully and may be part of the problem.

If you are sure the plug wires are in the right place, then maybe you can
do a cyl. balance test.   With a tach attached, disconnect and ground each
plug wire in turn  and note the effect it has on the tach.  Should have
about the same effect for each cylinder.  If  on cyl. being out has little
effect, you can chase down why that cyl. is not carrying its fair share.

...or you can just bring the car over on Sat.

Darrin
-----------------------------------------
Darrin R. Hartzler
Senior Corporate Governance Officer
International Finance Corporation
Washington, DC
Phone: +1-202-473-0027
Fax: +1-202-522-1604
Office: F4K-144
e-mail: dhartzler at ifc.org

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Daniel,

Perhaps a dumb question, but is there a leak where the carb balance tube
goes?  Are your base gaskets in good shape?

To find a leak, I sometimes spray a little starting fluid around a
carburetor and listen for changes in idle speed as the fluid gets sucked
in, or spray some WD40 and see if it temporarily plugs up an air leak.  You
can also use an unlit propane torch, although I've found this to be less
effective unless the leak is HUGE.  Sounds like yours might be huge.

Best of luck!

John McMahon

-------------- Original message --------------
From: "Daniel Goldberg" <goldie at danielgoldberg.net>

> Curt,
>
> I put my hand over the left side primary and there's very little suction.
>
> My Corvair's idle has been somewhat erratic. On Saturday I tuned it and
set the
> timing. I also installed the carb stabilizing kit I purchased from Lon
Wall in
> 2003 (really, I purchased it from Lon Wall: I was in McMinnville, OR at
the
> Corvair Underground and he took my money). My 'Vair is now running very
well,
> though since Oklahoma sells only 91 octane gas I have some pinging (will
retard
> the timing a bit to rectify -- or are there other suggestions?).
>
> However, my idle is still somewat erratic. Sometimes it's over 1000 rpm,
> sometimes under 500. I'm thinking the fact that there's so little suction
on the
> one side is a source of the problem.
>
> No?
>
>
> > ----- Original Message -----
> > From: "Curtis Shimp"
> > To: novacc-list at corvair.org
> > Subject: Re: [NoVa-Corvairs] tech question
> > Date: Wed, 20 Jun 2007 08:12:31 -0400
> >
> >
> > Daniel:
> >
> > Before we go into the possible places for a leak, and there are some,
> > what is it that make you think that you have a vacuum leak?
> >
> > Curt
> >
> > On Tue, 19 Jun 2007 22:06:03 -0400 "Daniel Goldberg"
> > writes:
> > > Why would a primary carb that's snugly tightened have a vaccuum leak?
(The
> > > line to the vaccuum advance is also properly plugged up.)
> > > _______________________________________________
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> >
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