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Re: Tach rebuild

To: enof <enof@earthlink.net>
Subject: Re: Tach rebuild
From: Steve Laifman <SLaifman@SoCal.RR.com>
Date: Wed, 02 May 2001 08:23:56 -0700
enof wrote:
> 
> Thanks for Lister/TigersUnited help with my Tach rebuild
> but
> when I went to adjust it
> I cannot get it down to the correct idle speed ~600rpm
> the lowest it will go is ~1200
> do I have a broken electronic part in there
> or do I need to add a resistor inline to the variable resistor
> or is it a variable resistor?
> 
> enof
> B9472075
> LAUGH NAKED :0)


The stock automatic choke is hot-air operated from the exhaust manifold
stove, not electrically operated, so there is no place to put any
resistor.  If there is an electric choke fitted, it is not stock, nor
may your carburetor be a Ford product, or follow the exact instructions,
clearances, jetting, etc. given for a stock carburetor.

You may not have the automatic choke, or cam adjustment, correctly set,
(hot air, or electric) and even if electric, no resistor is needed or
wanted. Your problem is mechanical or fuel/air related. Maybe from
obstruction in internal passages, maybe from bent adjusting linkages,
maybe???? Yes, there could be a broken part in there.

If you do NOT have an original carburetor, it is easy enough to get a
re-built at Pep Boys and use it, rather than mess around with one you do
not have the instructions for, or the trouble-shooting experience with
this particular device to find what is bent, mal-assembled, plugged,
whatever. They are not expensive, and they will take your own non stock
carb in trade. (if you re-assemble it)

Here are the idle mixture adjustment instructions from the Manual
(extracted and paraphrased), but this does NOT sound like your problem.

If I were to just guess, I would believe that the cold idle cam and
linkage are not properly assembled or some of the linkages in it are bent.


Section C, Page 16 of Rootes Tiger Workshop Manual recommends idle fuel
mixture and speed adjustments after all float level and automatic choke
adjustments have been completed.

Then, it is adjusted twice. Once for warm engine operation, and then the
idle speed is adjusted again (through choke operated "fast idle" screw
adjustments against fast idle cam) for cold idle.

For warm idle, the needles are set 1 to 1 1/2 turns out from full
inwards position. Do not make the needles tight against the seat, as
they may be damaged.

Operate engine for 30 minutes at 1200 rpm (idle speed adjustment), or
until stable operating temperature is achieved. Choke should be fully
opened. at this point. If not, adjustment is required.

Adjust idle speed to about 575/600 rpm (for standard engine), with idle
speed control screw. Make sure anti-stall dash pot is not interfering
with throttle lever.

Turn each needle mixture crew inward until idle speed begins to drop
from a leaner (in is lean) position, and then each is turned out until
idle speed increase, then begins to drop from rich mixture. Turn needles
in for maximum rpm and smoothness.

Both  needles should have been turned about the same amount. The final
setting should have no more than 1/2 turn difference between needles.

Then you adjust the choke fast idle position.

There are a "pot" full of other adjustments to be made before this
operation, and the manual should be followed for the correct order.

Steve
--
Steve Laifman        < Find out what is most    >
B9472289              < important in your life     >
                               < and don't let it get away!>
<SLaifman@SoCal.RR.com>
<http://www.TigersUnited.com/gallery/SteveLaifman.asp>

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