>Alicia & Dan
I agree with the several people that said
the empty PC valve is the problem. What was missing
is the statement that the PC valve controls the air
leaking into the base of the carb. (to allow the
blowby from the motor to be sucked into the intake).
With no guts in the PC valve the carb runs way too
lean. On the old Ford 2 barrel the PC circuit inside
the carb can be tested by replacing the PC valve with a
plug having about a 1/16" hole in it for an air bleed that
simulates a normal good PC valve at idle. The good PC
valve will open a bit more at high speed when the
(rattle valve) inside the PC valve opens due to more
blowby pressure and more vacuum from the motor. The valve
is gravity operated and a good coating of crap inside the
PC valve will change the calibration. This is one reason
that it is recommended to replace the PC valve at each tune up.
(They are very hard to clean inside even with a good solvent).
The area under the carb receiving the blowby via the
PC valve can get clogged with carbon. When this happens
it is also difficult to adjust the carb due to the mixture
being too rich ( opposite your problem).
The other valve cover must be vented to allow
the PC valve to do it's job. On my Tiger II the oil
filler cap is vented via a hose to the inside of the
air cleaner. This provides clean air to replace the
blowby being passed into the intake by the PC valve.
A clogged up breather (oil filler cap) can
cause a tremendous amount of oil smoke. The vacuum of
the intake via the PC valve will cause oil mist to be
sucked into the intake through the PC valve.
I had a problem with a 2 barrel Holly this year
where the choke didn't work right. The problem was
carbon blocking the passage from under the carb, through
the carb casting to a small piston in the choke assy.
The passage, when clear, caused the choke plate to be opened
somewhat under acceleration when the motor was not
completely warmed up. With the passage way blocked with
carbon the choke plate did not move on acceleration
and the motor bogged bad due to the overly rich mixture
caused by the accelerator pump shot and the closed choke
plate. I used a small drill bit (hand held) to clean
out the passage way. It was completely full of carbon.
The carb must be completely disassembled and cleaned
even in the places you didn't know existed if
you expect the carb to work correctly when you put it
back together.
This same carb had a damaged body gasket and a
leaking power valve in addition to the choke problem.
Milage changed from 12 to 19 mpg in town after the rebuild.
( This is on my Alpine with a 2.8L V6).
James Barrett Tiger II 351C and others
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