Re: Basic Spica questions from a rookie...

[Scott Fisher <sefisher@domain.elided>]

Bryan Carter comments:

> On my pump
> there is a three position lever and a spring that fits
> in a notch to hold the lever in one of the three
> positons.  None of the books explain what this is or
> show it in any of the photos.  What is it and does it
> have anything to do with my rich running condition at
> high speed?

It may have something to do with it, but there's more to look at.  It's
a temperature compensation lever.  Later Spica cars apparently did not
have it, but my '74 Spider has such a lever (a fact I verified two weeks
ago when I was replacing the air filters and giving the engine bay a
good cleaning), and my car's owner's manual describes its intended
operation.

If you look closely, the lever can be placed at one of three positions
marked N, C, and F.  These stand, says the manual, for the English words
Normal, Cold, and Freezing.  N is to be used when temperatures are above
59 degrees F; C is for temperatures between 59 and 32 degrees F; F is
for when temperatures are below freezing.

In asking the collective wisdom of the Alfa Digest about this, the
general consensus was that even in New England winters of yore, the cars
ran best and gave best fuel economy with the lever left in the N
position.

So... if your lever is in a position *other* than N, this may be
responsible for your failing the 2500 RPM portion of the test, because
the lever would enrich the mixture to compensate for colder, denser
ambient air.  It's certainly easy enough to look and give it a flip if
required.

However, you may also benefit from a piece of advice given me recently,
first in person at the Historics and later (because I was puzzled by
some of the terminology used -- I hadn't looked hard at the Spica yet)
by way of a published letter and illustration in the January issue of
our club magazine:

If you pop the hood of your Spider, you should easily be able to see
that the throttle cable rotates a pulley between the #2 and #3 intake
tracts; this pulley in turn presses down on two rods, a short one and a
long one.  Each rod has a small ball joint at each end, held in place
with locknuts.  The short rod connects to the throttle butterflies; the
long rod goes down to the Spica pump and is in fact the throttle
position sensor for the Spica, one of its three inputs (along with
temperature and RPM) for metering fuel.

The trick I was told is this:

Loosen the locknuts on the longer of the two throttle rods.  Rotate the
rod two full revolutions -- that is, 720 degrees -- in the position that
will make it *shorter* than it is now.  This will trick the Spica into
thinking the throttle is not depressed as fully as it really is,
effectively leaning out the mixture that you say is too rich.  

Once you take the test, reverse the procedure, making the rod *longer*
than it was for the test.

I haven't needed to try this trick yet (my '74 Spider passed the
California test last May with no trouble, but I'm keeping my fingers
crossed for the future -- and also using synthetic oil to help minimize
the wear).  However, it comes recommended from a source that certainly
sounded authoritative, both in person and in the published tip.

And of course, the usual smog-test procedures apply: use new spark
plugs, warm the car up fully before the test, and make sure the oil is
fresh.  Yes, really; old oil can cause a car to fail smog for a number
of reasons (excess vaporization, blowby, contamination with fuel, etc.)  

Best of luck,

 -- Scott Fisher
    Sunnyvale, CA

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