<VV> Rough idle
Stephen Upham
contactsmu at sbcglobal.net
Sun Oct 4 10:38:57 EDT 2009
I drove the car yesterday. I took it to our 50th anniversary party.
This was almost an exclusive highway trip being on street roads only
for about five of the 150 mile round trip. The car started up and
ran well to the highway from my house which is about mile. It ran
great to the celebration site. I was late and was going 65 to 70
most of the time for the 60 miles. When I came off of the highway
and hit my first stop light, the rough idle appeared. It stayed that
way as long as I was idling. Once the gas was applied, even
sparingly, the condition seemed to improve. We took a look at it at
the show. Removing a spark wire from the left side cylinders gets
the anticipated response of loping of the engine, and in fact, if any
one of them is left off, the engine acts like it will die. When the
same thing is done to cylinders on the right side, there is no effect
on the running of the engine at all. I took off the carb top and
again tried to see if the idle circuit was clogged. I used a
telephone wire, first sheathed and then unsheathed. It will go down
the tube 1 1/2 inch and stop either way. One other interesting
thing, is that, although I have a 110, I have dual exhausts. After
idling in the garage during the idle circuit work, I put my hand to
the exhausts to see what the force of the exhausts is; the left side
was predictably warm, the left side was cool, indicating, to my
admittedly limited knowledge, that there is no fire on that bank. I
do have a set of new plugs, they are the R44F's, but have not
installed them, nor pulled the plugs on that side to check them yet.
The electric components are less than 7K miles old on an engine that
also has less than 7K miles on it. That includes the Pertronix
ignition, the distributor cap, the Flame Thrower coil, the plugs, and
the Emerson silicon wires. The carbs are less than 500 miles old
after a complete and profession rebuild. I have an inline filter
before the electric pump (working great) and a Purolator fuel flow
restrictor set at 2 1/2 (though probably not necessary as the pump
meets the original Corvair specs for fuel flow). I have pulled the
hoses for the possible vacuum leak areas for the carbs and found
absolutely no problems. I have sprayed the base of the carbs with
carb cleaner an not seen any appreciable rise in rpm. I have re-
torqued the carb attachment nuts to 11 ft. lbs. and retightened (not
over tightened) the air horn screws.
Thoughts?
Stephen Upham
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