Folks:
I have been driving the 6 more in the last week than I have in
the 3 years preceding. 'Course considering the fact that the 6 was
sitting in the corner of the garage in boxes for the last 3 years may
have something to do with that...
Ahem. Back to the original intent of the message.
I have noticed a tendency for the 6 to idle roughly when first
started after being driven and parked for more than a few minutes. If I
drive it down the road for a mile, the idle smoothes out nicely. The car
never hesitates, burps, misses or does anything else that indicates a
problem. Just the rough idle immediately after a warm start.
My spark plugs read an even grey/tan color. Timing is stock
10BTDC static, 4ATDC dynamic. My compression is 9.6:1, and I have a 270
degree camshaft, stock exhaust, stock ignition, ZS carbs with B1AR
needles. The mixture fine adjust screw is fully closed, and I have set
the deceleration bypass valves per Bentley. Warm idle is about 900 RPM,
cold idle is about 1500 RPM with the choke engaged. I never need to use
the choke once the car is warm, and it will start effortlessly when it
warm. All emissions systems are in place and working.
I have been thinking about this, and it seems to me that this
may be heat soak of the carbs. I rebuilt the carbs ages ago, but never
touched the mixture temperature compensators other than to replace the
covers. My car will not pass the "lift the slide" test when idling, but
I have been attributing that to the cam.
Any suggestions as to what to check? I am suspicious of the
mixture temperature compensators, but that is just a WAG. Fuel
percolation? Lean idle mixture?
As always, thanks for any help.
Vance
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