Martin,
Maybe I can help.
> 1) Only the vapor hose from the tank connected to the carbon canister. (The
>anti-run-on
> switch in the base of the canister was gone before I ever got the car ...but
>the SU's
> tune down to an idle low enough not to matter.)
No problem there.
>
> 2) There are no "float chamber vent tubes" on the SU's to connect in an
>anti-run-on configuration.
If you want to be environmentally correct, you can take the float bowl
covers off, drill out the existing vent holes to a size that would
correspond to the O/D of some small brass tubing. "T" the two float
bowls together and run that line down to the charcoal cannister.
>
> 3) The manifold is vented in a "T" configuration back to the large intakes on
>both
> carburetors.
That's your negative crankcase ventilation--necessary on a Spitfire.
>
> My question is this -- do I need do anything more with the carbon canister?
>Shouldn't
> its float chamber vent port be plugged, and the center purge port be vacuumed
>off and
> back into the system? Has anyone else figured this one out?
> Hook that port up to bowl vents (above) or just cap it off. Both of my
cannisters are vented into the back plate of the rear air filter.
Theoretically, the charcoal collects all the fuel vapors while the car
is not running. When you start the car, the air filter chamber should
create just enough vacuum to draw off the fumes, without providing so
much vacuum that you start sucking gasoline from the fuel tank.
Works for me,
Charlie B.
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