Vance, I've had what I believed to be a heat soak problem ever since
I've owned my car (5 years), during which time I rebuilt the carbs with
no change to this condition. After sitting around for 10-15 minutes the
engine is hard to start, and when it does I could smell gas for the
first few seconds after it started. I tried a makeshift temporary
heatshield but it didn't really help much. About a year ago, someone
gave me a tip to set the floats lower. I finally got around to it a few
weeks ago and notice a definite improvement in hot starting. Problem
not totally solved but much better. I wound up setting the float to
0.70 inches instead of the 17 mm spec (0.67 inches), a difference of
only 0.030 inches. Perhaps a higher float setting would eliminate the
problem altogether, but for now I am happy.
John - 76 TR6
Vance wrote:>>
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?
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