Non starting Mercedes 190 (Carb)

Recently bought a good condition 190, ran OK cleaned up nice. Car will not start now, fuel pump is working, strong spark at the plugs, fuel in the tank, good battery. The manual I have with it is not very clear on the
carb and associated equipment attached to it. Is there a switch somewhere I do not know of, or is there a more expensive problem. Any thoughts and suggestions?? Thanks
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It cranks but won't start?
Fuel filter OK?
If so, the carburetor is suspect.
Carburetors have chokes - a flapper plate at their air intake. When the engine is cold that flap ought to be closed to restrict the air volume and so enrich the air / fuel mixture for starting and initial warm up. As the engine warms the choke opens until it's wide open at the engine's normal operating temperature. Choke opening and closing is usually done (on most carbs) by a bi-metallic spring that gets heated by the engine. If the choke plate is not shut then you need to find out why not. The linkage could be dirty and binding. If it's shut then you need to check if fuel is being supplied to the engine.
You can check if fuel is supplied to the engine by looking into the carburetor - push the choke open and pump the accelerator. Don't crank the engine, use a flashlight to see NOT a match!! You should see gasoline being squirted into the venturi by the carb's fuel jets. If not, then either the carb is dry or the accelerator pump is kaput.
The carb would be dry if the needle valve that regulates the fuel flow into the carb is stuck shut by gum or dirt. Try tapping, NOT rapping, the side of the carb while cranking the engine - it may loosen the needle. If not, the carb must be cleaned ideally by adding cleaner to the fuel or (aaarrrrhhhh) disassembly, cleaning and reassembly using new gaskets (usually sold as a kit). If you've never rebuilt a carb number every piece as it comes off or out and bag them so all the pieces go back in. It's not hard but must be precise. The float's level inside the carb must be correct to allow the carb to supply the correct air / fuel mixture. A kit includes a float gauge (templet) to check the float's tang position (that controls the needle valve). (This is somewhat similar to the workings inside a toilet tank, simple once you know the concept.)
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