Listers--
My 76 '6' has about 50k original miles on it and only burns oil when
warming up, probably due to bad valve guides. Compression is
decent--around 125 with no more than 12 lbs. differential between 2
cylinders. Problem is it has a mild-to-moderate sputter under load, such
as when accelerating up a very slight incline. Whenever it's idling or
backing off down a hill, it's as smooth as a silk. Here's what I've done:
--totally cleaned ZS carb pistons & upper bowls and replaced diaphrams
and needles
--all new bosch points, plugs, condenser, cap & wires
--new air filters
--vaccuum advance checked and working
--installed new small black vaccuum fittings
--removed and decarbonized the EGR valve and manifold tube; verified that
the EGR will hold a vaccuum & rises and falls with engine speed changes
--balanced carb air flows with a unisyn
--mixture adjusted with a color tune to bunson blue (although i never was
able to get these emission carbs to show yellow unless i'm pushing down
on the adjusting tool)
--using marvel mystery oil in the dashpots
--valves, points, plugs, timing, dwell, idle all adjusted according to
the book
--followed the bentley manual, unisyn and color tune instructions to the
letter
a few things i'm suspicious of:
--i think i hear a vaccuum leak in the brake servo (rebuilt using the
standard "rebuild" kit which really is a joke)
--there MAY be an exhaust leak near the number 6 cylinder
--when working with the EGR valve i noticed the screw head on top was
loose, so i tightened it all the way down.
--i have not been into the lower part of the carbs
--i still feel like i'm essentially guessing with the color tune because
i can't get it to show yellow consistently on either carb (yes, the
needles are engaged and i can fully retract them until they stop turning)
but i have experimented at different mixture settings & still get the
sputter.
has anyone else experienced, solved this problem?
Thanks
--Ian CF57345U
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