I took the Club Ford ('75 Zink Z10) to Thunder Hill last weekend. It was
running fairly well in the morning, but as the day wore on, part-throttle power
decreased considerably. By the end of the day, I pretty much had an on/off
switch for an accelerator.
The plugs were fairly oily. They looked like the mixture might be too rich as
well, but I don't have enough experience to tell (especially with the oil on
them).
I tried a different coil, which helped for a short period, but then it started
getting worse again.
I thought it might be the battery, but it ran the same when hooked up to the
starter battery.
The engine did not seem to be running any hotter than it was in the morning.
I checked the points gap. I tried different spark plugs. No change.
I've developed two theories that might match the symptoms:
1) the diaphram controlling the full-power valve is torn, making the mixture
too rich at part-throttle (when the inlet vacuum should be closing the valve)
2) something else is off calibration in the main barrel, and it runs OK at full
throttle after the secondary opens up.
Note: the carb is a two-barrel, sequential (Weber DGAV).
Any ideas? Does either theory seem plausible? Would you suspect the carbs or
the ignition?
-- Jeff.
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