Re: Starts easily when cold, but won't idle when warm

[Matt Haas <mhaas@xxxxxxx>]

I agree. I had a similar problem with the six cylinder in my 68 American 
(manifolds were loose due to worn out fasteners). Squirt some WD-40 (or 
other light oil) where the manifold meets with the heads and at any vacuum 
fittings in the manifold. If you find that the intake manifold is loose, 
you may want to put new gaskets on it. Also, make sure that you follow the 
torque sequence in the TSM when you tighten the bolts.

Matt

At 02:36 PM 9/30/2005 -0700, you wrote:
> Jerry,
>
> You have a vacuum leak I think.  When the choke opens
> the extra pulled in by the leak makes the mixture too
> lean.  It won't idle when it is too lean.
>
> Regards,
> Joe Fulton
>
> --- Jerry Phillips <jnpvegas@xxxxxxxxxxxxx> wrote:
>
> > The engine ('68 390) starts fine when cold, but when
> > the choke starts to come open, rpms start to drop
> > and it is necessary to bump the throttle to keep it
> > going.  The slowest it will run is about 1,200 rpm
> > at steady throttle, anything slower and it stalls.
> >
> > New:  Plugs, wires, coil, points, condenser, cap,
> > battery cables, relay, relay to starter cable
> >
> > Replaced: rebuilt Holley 4160 (vacuum secondary) 600
> > cfm with electric choke
> >
> > Timing at 5 degrees BTC, at 700-800 rpm in neutral.
> >
> > I have tried it with the idle mixtures screws at one
> > and one half turns out, as recommended in the Holley
> > rebuild kit literature, up to three turns out as
> > recommended on the Holley web site.  Doesn't seem to
> > matter, it still stalls as the choke plate opens
> > out.  As the engine warms up, the only thing that
> > keeps it running is more gas.
> >
> > Anyone got any ideas?
> >
> > Thanks,
> >
> > Jerry Phillips
> > Las Vegas
> > '68 AMX 390

mhaas@xxxxxxx
Cincinnati, OH
http://www.mattsoldcars.com
1967 Rambler American wagon
1968 Rambler American sedan
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