[6pack] Rich mixture and O2 sensor

[John North]

I am trying to resolve an air/fuel problem on my K&N gauge and sensors
which give a reading in the 12-13 range on the gauge.   Also
accelerating from tight bends in autocross, the engine bogs down and
blows black smoke.

The plugs don't look bad.   1 and 6 are a little dark, the rest are a
light  brown.   Adjustments to the carb needles had zero impact on the
A/F reading at the gauge.   So I have replaced the carbs with a
rebuilt set however, the reading is still in the 12s with the needles
at full lean.

I used the Gunson colortune and it shows a blue flame at idle, yellow
flame for a second or two when I blip the gas, then settles to a nice
blue flame between 2000 and 4000 rpms.   Not sure whether the initial
yellow is how the carbs should work, maybe this could be contributing
to the bog down on acceleration through corners.

So maybe the gauge is faulty??   Or the sensors (I have two on the
downpipes with a switch to change carbs)??

Someone suggested that the autocross problem may  be floats set too
high sloshing fuel around, so in the rebuilt carbs I lowered them to
the lowest tolerance in the manual.   Haven't had an autocross event
yet to test this out.

Any suggestions as to how to test the sensors and gauge?   Any help
appreciated.   Autocrossing in this condition is embarassing...

John North
1976 TR6