[ Ref. Duaine Hechler in 120622 MMDigest ]

Hi Duaine,  I'll make a couple of assumptions and then suggest some
solutions.

Assumption #1: You have replaced the leather "doughnut" that surrounds
the hole in the take-up spool that is covered with the paper, or are
satisfied that the one there is of sufficient suppleness and nap to
provide a good seal with the paper.

Assumption #2: You have either replaced the rotating bearing in the
left-hand end of the spool with one of the machined Teflon bearings
that Bob Streicher used to make (and perhaps still does), and that
bearing, or the original one with the packed leather washers are
appropriately lubricated.  (More on this in a subsequent posting.)

Hypothesis: The brass fitting that goes through the wall of the
spoolbox between the take-up spool and the tubing connected to the
left-hand end of it is leaking.

How, you might ask, is this possible?  Well, I will tell you.  Remove
the tube from this fitting and attach a longer tube through which you
can apply mouth suction while covering the spool end with a finger.
You _should_ be able to draw a hard vacuum with no leakage whatsoever.

However, I expect you will be able to feel a very slight leakage.  This
is due to the minute opening of the longitudinal seam in the small
diameter tube resulting from how this tube was fabricated.  Due to
oxidation and acquired patina, this seam may be difficult to even see
until you remove it and use steel wool or a wire wheel to clean it up.

When installed, this leakage is not enough _by itself_ to trigger
cut-off, as you note when you place your finger over the shaft end.
However, with the spool installed, the _combined_ small leakages from
the seam, the spool bearing and the paper-sealed washer is just enough
to cause a spurious cut-off.  Frequently, this is an intermittent
issue; it can be fine one day and fail the next.  This also contributes
to customer frustration.

Solution #1 (Best) -- Thoroughly clean and de-grease the brass fitting.
An ultrasonic bath in an ammonia solution is recommended.  The tube
seam should then be readily visible.  Apply soldering flux to the
length of the seam and use a propane torch or high-wattage soldering
iron to seal the seam.  High-strength or "silver" solder would be the
best choice, but regular electronic or plumbing solder should also
work.  You may have to use sandpaper or a fine grinding tool to remove
any solder that remains above the surface of the tube as this will
prevent it from passing smoothly through its journal on reinstallation.

Solution #2 (Quicker but possibly not as long-lasting) -- Increase the
size of the bleed hole in the primary valve one, or at most, two drill
sizes to compensate for this leakage.  If operation is still "iffy"
after two sizes larger, apply Solution #1.

I have encountered this problem in roughly 75% of the Ampico A's
I have restored.  Zoe, if you are reading this (as I'm sure you are),
I believe your similar problem may require a deeper intervention, but
it _will_ be solved!

Regarding the odd chain position, I'm guessing the chain idler is not
tight enough, the chain came off of the driving gear, and the customer
turned the take-up spool by hand in an attempt to get it to do something,
thereby wrapping the chain around the front gear.

John Grant