Here is the
Holley 1945 operation and repair manual (pdf), and here is the
Chrysler training film on the Holley 1945.
Here is the
Holley 1920 operation and repair manual. Discussion threads about 1920 repair are
here,
here, and
here, and there's a big discussion thread about 1920 modification & upgrade
here.
Here is the
Carter BBS operation and repair manual (pdf). More-or-less-reliable specifiation and adjustment information for many BBS variants used in the US/Canada and export markets from 1960 to 1977 are
here.
Here is the
Carter BBD operation and repair manual (pdf)
There is a Chrysler training movie on the Holley 2280 over
here.
This site has a choke and carburetor adjustment article with links to carburetor-specific information
here.
Additional Chrysler-made movies related to carburetors can be found
here, and more paper documentation can be found
here.
Setting the idle adjustments
There's no spec for where the mixture adjustment screw should be in terms of turns in or out, so don't follow advice that starts and ends with "Set the mixture screws two and a half turns out". If you don't have an exhaust gas analyser, which most of us don't, and you're not using a ColorTune glass spark plug to set the mixture by the appearance of the combustion flame (buy one
here), then the best you can do is to adjust by engine behaviour.
If you're starting with a freshly installed carburetor or the idle mixture is way off, first turn the
mixture adjustment screw(s) clockwise until they
lightly seat—don't turn them down tight, or you'll spoil the carburetor—and then back the mixture screw(s) out anticlockwise 2½ turns. This is not the final adjustment, it's just getting the screw(s) into a position near the right ballpark so you can find the right adjustment.
Make sure the ignition system and PCV system are all in good shape, plugs and PCV valve are clean and working correctly, ignition timing is set correctly, and valves are adjusted. Get the engine thoroughly warmed up, all the way up to full operating temperature, connect a tachometer, and then you're ready to work with the idle speed and mixture adjusting screws.
Use the curb idle speed adjusting screw (the one that doesn't seat on the fast-idle cam) to set the idle speed to between 600 and 750 rpm. Then, go round the other side of the car and adjust the mixture screw(s) clockwise ¼-turn at a time, slowly, pausing for a few seconds after each ¼-turn, until the engine just begins to drop RPM because it's too lean (you can use your ears to detect this, but watching the tachometer helps). Then, turn the mixture screw(s) back anticlockwise ¼-turn at a time or so, again working slowly and pausing, and keeping careful track of the number of ¼-turns, until the engine just barely begins to drop RPM because it's too rich. Then, you turn the mixture screw(s) clockwise
half the number of quarter-turns you counted between lean fall-off and rich fall-off, and that's your final adjustment. Then re-check the idle speed and readjust to 650 rpm (use the tachometer), and you're all done setting the idle mixture and speed. You want the final adjustment of the screw(s) to be in a clockwise direction, so spring tension doesn't change the adjustment over time.
Sometimes you will not be able to find the rich dropoff point, because the carburetor is designed not to permit an overly-rich idle mixture. In that case, the best you can do without an exhaust gas analyser or ColorTune is to find the lean dropoff, then carefully back the mixture screw(s) anticlockwise just ⅛ turn at a time until the speed stops increasing (watch the tach!), then clockwise ¼ turn. Then use the idle speed adjusting screw to adjust back to between 600 and 750 rpm, and you're done.
On a carburetor with two idle mixture screws—many but not all 2bbl and 4bbl carburetors—it's important that the mixture screws be kept in sync.
Cold-engine start & stall issues
Cold-engine hard-start, stalling and rough running issues are usually choke-related; an
electric choke kit is often a wise choice if your present choke thermostat is old or faulty, and the carburetor's choke pull-off may need adjusting. Choke adjustment information is
here.
General advice
Always avoid "remanufactured" carburetors for the reasons discussed in
this thread.
It is practically impossible to buy good quality, complete carburetor kits through normal parts-store channels any more. Spend the extra money to buy a complete kit from the likes of Don Hargrove's
The Carburetor Shop; it is well worth the extra.
Problems that seem to be carburetor-related are often alleviated by doing the
fuel line mod.
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