<VV> Chasing a stumble

[Devin]

Hey gang-  My 63 102hp has been giving me fits for quite a while now and =
I
just can=92t seem to work the stumble out of it.

=20

What it=92s doing:  While cruising in town at 27-35, sometimes 40 mph in =
3rd
gear it will stumble bad enough that it will cause the shifter to jerk =
back
and forth front to back nearly a foot, and it obviously shakes the rest =
of
the car as well.  This only happens while maintaining steady speed or =
very
little acceleration.  It does not happen in 1st or 2nd, I=92m though =
that rpm
range too fast.  I have not been able to get it to do it in 4th either, =
even
when I try to duplicate the same rpm.  I think it=92s about 1500 to 1800 =
rpm,
but I don=92t have a tach so I can=92t be sure.  I=92m guessing that it =
is in the
transition between the idle circuit and the main circuit on the carbs.  =
It
also has a bit of a miss at an idle, especially while cold.  It does =
tend to
stumble harder while the engine is cold, but it still occurs even while
warm.

=20

Trying to eliminate this I have rebuilt the distributor, as the timing =
was
bouncing around 6-8 degrees.  Point plate moves smoothly.  Installed a =
new
bushing, new points, condensor, cap and rotor.  Timing is set at 15 =
degrees
initial and 36 total with a dial back timing light.

=20

I rebuilt the carbs a few weekends ago, now convinced that the problem =
was
there.  They had been redone about 12000 miles ago and it ran fine then.
The floats float, and are set according to the 63 shop manual.  I also
installed a new needle and seat, all new gaskets, including using the =
thick
main body gasket included in the kit, same as what was in there already. =
 I
sprayed out all passages with carb cleaner and blew out with compressed =
air.
I used new base gaskets and sync=92d per the manual and did the final =
fine
adjustments with a Unisyn.

=20

I run 87 octane gas without any noticeable detonation. =20

=20

I=92m at my wits=92 end.  I=92m tired of chasing the same problem round =
and round
with no success.

=20

I have yet to pull the plugs out for inspection, rather dumb of me I =
know.
I was going to tonight, but couldn=92t find my rubber insert for the =
plug
socket so I gave up and came inside.

=20

What have I missed?

=20

Devin


--=20
No virus found in this outgoing message.
Checked by AVG Free Edition.
Version: 7.5.446 / Virus Database: 268.18.7/711 - Release Date: 3/5/2007
9:41 AM
=20