Re: [Amc-list] Carb adjustments - Holley 1909 one barrel

[Tom Jennings <tomj@xxxxxxx>]

For nearly all carbs, the idle mixture screw (slotted, knurled, spring 
under it) is IN=LEAN. It's a gasoline bleed, so out is more gas. There 
are a few that it's an air bleed, RTFM the TSM... or someone here will 
know that 1909.

The TSM should say, but usually the routine is, screw it in all the way 
(GENTLY!!), then back it out 1.5 - 2 turns. That should run well enough 
to start.

This is the "old timer" method that will get you within 10% of what you 
could do with gas meters and all that nice stuff.


YOu sorta need to adjust the carb twice. First, get it warmed up.

Once warm, make sure the choke is fully open. If not, for now, loosen 
the screws around the black cover and turn it LEAN until it is (eg. put 
this off til last). This also means that the warm-up fast-idle setting 
will have no effect at this point. Put that off til 2nd last :-)

Find the idle-stop screw, set the idle to as low as it will run 
reasonably. Then tweak the idle MIXTURE screw for the fastest idle 
speed. If the idle is now "fast", back off the idle-stop screw to slow 
it down, and iterate until you get it fastest.

(An alternative method for this step is to use a vacuum gauge, and 
adjust idle mixture for highest vacuum.)

As a sanity check, the idle mixture screw should be still around 1.5 - 
2.5 turns. If it's crazy far in or out, there's a problem.

Then, turn the mixture screw in (LEAN) a tiny bit until you hear the 
idle speed drop "a bit", 50 rpm or so. It's about the smallest noticable 
speed drop. (Alternatively, until vacuum drops 1 - 2 InHg). That's 
called "lean idle drop". It's good for emissions and leaner idle is 
better than richer here.

Now set the idle-stop to the idle speed you want. It ought to be 
perfectly smoooooth.


Now you gotta wait for the motor to get cold!

Set the thermostat to 1 stop LEAN (or RTFM...). Open the throttle all 
the way and let go. The choke should partially or mostly block the carb 
bore; the fast idle screw should be resting on the stepped cam. It's 
likely hard to see.

You can eyeball it's operation by opening and closing the choke with 
your finger and see it step onto and off the cam.

Start the car. Without touching the throttle, adjust the fast-idle screw 
to be... "fast".

Once it warms up, opening the throttle should allow the (now hot) 
thermostat to pull off the choke and off the fast idle.

That's it.




> Finally - after replacing the head and head gasket, my car stopped
> smoking. I replaced the oil and oil filter, and did not have
> condensation on the inside of the valve cover last check - also no
> foamy stuff. I installed a rebuilt fuel pump, and a new section of
> rubber fuel hose. Now the car is smoking like a train. Do rebuilt fuel
> pumps have oil in them to keep them from rusting? Could that be it? Or
> do I have to start checking other things? The smoke is light in color,
> but has a little blue. It does not go away as the car warms up - but I
> haven't driven it very far since replacing the pump. The smoke is not
> black, and it is not as white as before I had the head rebuilt.

Bad idle setting won't cause smoke! I'd immediately pull a plug or two. 
It shoudl be beige, or brown, or even near-black if super rich (eg. 
stuck carb float etc).

If it's got goo on it, that's bad. If it's sticky, it's fresh. If it's 
not idling well, it could be something like that, check it ASAP before 
any harm is done...
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