Need to know how to properly set mixture of fuel and air on my carburetor

There are a few possible reasons why your Charade is producing black smoke, even after you have serviced the carburetor:

1. The carburetor may still not be functioning properly. Make sure that all of the carburetor's components are clean and functioning correctly.
2. The air filter may be clogged or dirty, which can cause the carburetor to mix too much fuel with the air. Check the air filter and replace it if necessary.
3. The fuel mixture may be too rich (too much fuel, not enough air). This can be caused by a variety of factors, including a faulty carburetor, a clogged fuel filter, or a malfunctioning oxygen sensor.
4. The spark plugs may be fouled or worn out, causing the engine to misfire and produce black smoke. Check the spark plugs and replace them if necessary.

iac valve idle air control valve if it not easy to start or hard to start if you hold the gas pedal a bit it doesnt stall check the idle air control thanks pierre let me now

That sounds like a fuel/air mixture problem.

Just to confirm .. it is a carburettor, not fuel injection?

As a general rule of thumb (with carburettors..) if it backfires through the exhaust/muffler .. the fuel mixture is too rich.

If it backfires through the carb/air filter, the mixture is too weak.

It could also be a 'sticking' float in the carb.

When an engine is cold the fuel is rich .. lots of fuel .. that's how a choke works.. However, when the engine warms up a rich mixture causes problems. The car may splutter and stall, run sluggish or cut out.

It sounds like the engine is running "rich". This means that the air-fuel mixture if off, and there is too-little air getting to the engine for the amount of fuel. Try replacing the air filter.

If your engine has a carburetor, the problem might be the choke or the mixture screws. Unless you are familiar with you carburetor and the settings for your engine take your car to a mechanic and have it set properly.

If your vehicle if fuel-injected, take it to a parts store that will run the engine diagnostic check. If the problem.id the engine, the diagnostics will reveal the problem.

There should only be 1 screw located at the base of the carb facing outward.

The method I use requires a tachometer. If you don't have a tachometer then you can use the "by ear" method, though it's not as accurate.

With the engine off, start by turning the screw all the way in, then back it out 1 and 1/2 turns. This usually give you a baseline to start with.

Start the engine and get it up to operating temperature, make sure the choke is fully open, and have the air cleaner and all vacuum lines installed.

Using the tachometer (or ear) turn the screw (usually out) until the RPMs increase. If they don't increase by turning the screw out, then try turning it in.

Eventually the RPMs will stop climbing while turning the screw (as said earlier, usually out).

THEN turn the screw the opposite direction (usually in) until the RPMs JUST start to drop off. That should be real close to the optimum setting.

This setting is ONLY for the base idle air/fuel mixture and is NOT for anything else.

Hope this helps.

Unless your engine has a carburetor, you can't adjust your fuel mixture. That is done by your cars computer. It analyzes your exhaust emissions and adjusts your fuel/air ratio.
Your oxygen sensor(s) may need to be replaced, or there may be a computer glitch causing the problem.

The air/fuel mixture screws are usually capped off and the adjustment might not be possible, but if the air/fuel mixture screws are exposed then turning them in will lean out the fuel mixture, and turning the air/fuel mixture screws out will en-rich the fuel mixture.

With the engine fully warmed up and at normal idle speed adjust the air/fuel mixture screws one at a time, and turn each air/fuel mixture screw in until the engine just begins to mis-fire, then back out the air/fuel mixture screw one and a half turns to two turns to achieve a smooth idle.

Be certain that the air and fuel filter(s) are not plugged up (there might be a fuel filter inside of the fuel pump as well as the fuel filter/stone at the fuel inlet to the carburetor) and keep in mind that the minimum octane requirement for that engine is 91 octane, and 92 octane is the average octane rating for the premium higher grade fuel, so a bottle of octane booster added to a full tank of fuel will greatly improve the way the engine idles and performs.

That engine should have an electronic HEI (High Energy Ignition) distributor with the large distributor cap and with the ignition coil inside of the top of the distributor cap, and keep the tune-up parts in good condition and replace them when they wear out. The tune parts would consist of the distributor cap, ignition rotor, spark plugs, spark plug wires, and the spark plugs should be gapped at .045 in.

For better performance from your El Dorado a 1 inch spacer under the carburetor will really help a lot if the hood clearance will allow it, and you will need to set the ignition timing to 10 degrees before top dead center, and adjust the accelerator pump on the carburetor for maximun pump efficiency so that as soon as the throttle is opened there is two healthy squirts of fuel from the accelerator pump, and they should squirt as soon as the throttle is opened, and if the throttle can be opened and the accelerator pump does not squirt fuel at the same time as the throttle is opened, then there will be a lag or stumble from the engine on take-off and a severe loss of engine performance. (The accelerator pump must pump fuel into the carburetor at the exact same time as the throttle is opened)

For better performance check the adjustment of the secondary throttle linkage, and let me know if you require assistance with any of the proceedures.

Be sure that the vacuum lines to the EGR valve are correctly routed and that the EGR valve is not operating at idle.

Also, that engine has a plastic timing gear that was used for the camshft timing gear, and I would seriously suggest that it is changed before trying to get any performance from that engine.

Other than those modifications, the engine would need a better camshaft and the catalytic converter removed to increase the performance of that engine.

Here are some images to help assist you.


Fuel Pump Filter:










Rochester Carburetor Secondary Adjustment:

Hi..
A few clarifactions pls...
Which Car....
Does it have a carburetor or a Multi Point Fuel Injection System
Diesel or pertol or Gas.

The most basic reason for poor emission is incorrect mixture of air and fuel.
if carburetor then you will have to get the correct mixture set . Its NOT a long procedure just adjusting 2 main screws.... But lat a mechanic do it.

If Multi point fuel Injection... then the injector needs to be cleaned This is a lengthy affair. Before opening this you could use fuel additive ment for cleaning the injectors..
Alos check if the manifold/ exaust pipe is not leaking from anywhere as this reduces the pressure and the burn is not total resulting in Emission..

There are fuel addetives that help clean the engine from inside.... but for that I would need more info so as to guide which addivive could be suited.
Regards
Berry

carb problem or vacuum leak at carb base gasket or intake manifold

There should be one screw (I'm assuming it's the Carter YF carburetor 1 barrel) that's by itself away from linkages etc, more to center at base of carb where it meets manifold, that is angled approx 45 degrees going in to base. That should be your mixture screw. What symptoms are you experiencing anyway?