Re: Backfire thru carb. - Advance or retard?
Wires don't always have to be switched to create crossfire -
but switching is definate!
Plug wires laying parallel for too long a distance causes
cross induction - same symptoms. The magnetic field around
the correct wire induces enough voltage in the wire next to
it that it fires too - in the wrong cylinder at the wrong
time. Tying wire so they look neat looks good, but doesn't
work so well.
Try separating the wires better. Also look for whitsh marks
along each wire - indication of insulation breakdown. Spark's
jumping through at that piont.
Or - When you changed the plugs you may have inadvertantly
broken the connection at the end. Now it's an open wire -
or partially open.
A partially open wire is much harder to fire - sometimes it's
easier for the spark to jump across the terminals in the
cap, or even jump to the wrong wire.
The cure is replace that broken plug wire - or re-end the
Sometimes the symptons are under acceleration, deceleration,
cruise or even idling - unpredictable when it does it.
And it could just be an insulation problem, occasionally the
spark jumps to ground somewhere. Easy way - usually - squirt
water around with a Windex spray bottle on the ignition wires,
plugs, cap, coil etc. When you feel a tingle or hear a misfire
you found it.