1. Carburetor Issues: This is the most probable cause. Problems could include:
* Dirty or clogged carburetor: This is the *most common* issue with older carbureted vehicles. Dirt, varnish, and gum buildup restrict fuel flow, leading to rough idling, hesitation, and stalling, especially when cold. A thorough cleaning or rebuild is often necessary.
* Faulty choke: The choke helps enrich the fuel mixture when the engine is cold. If it's sticking, malfunctioning, or not opening properly, the engine will struggle to start and run smoothly when cold.
* Bad accelerator pump: This pump provides an extra squirt of fuel when the throttle is opened suddenly. A weak or failing pump leads to hesitation and stalling on acceleration.
* Incorrect carburetor adjustment: The carburetor needs to be properly adjusted for fuel/air mixture and idle speed. Improper adjustments can cause many of the symptoms you're experiencing.
2. Ignition System Problems:
* Worn distributor cap and rotor: These components distribute high voltage to the spark plugs. Worn or cracked parts can cause misfires, leading to rough idling and poor performance.
* Faulty ignition coil: A weak or failing coil won't provide enough voltage for a strong spark.
* Spark plug wires: Cracked or worn wires can cause misfires.
* Spark plugs: Worn, fouled, or incorrectly gapped spark plugs are a common cause of poor engine performance.
3. Fuel System Problems (beyond the carburetor):
* Clogged fuel filter: A restricted fuel filter can starve the engine of fuel, causing similar symptoms.
* Fuel pump: A weak fuel pump might not deliver enough fuel, particularly under acceleration.
Troubleshooting Steps:
1. Start with the easy checks: Inspect the spark plugs, wires, distributor cap, and rotor for visible damage. Replace any that look worn or damaged.
2. Check the fuel filter: Replace it if it's old or dirty.
3. Focus on the carburetor: This is the most likely culprit. If you're comfortable working on carburetors, try cleaning it thoroughly. Otherwise, consider taking it to a mechanic specializing in older vehicles. A carburetor rebuild kit is usually readily available.
4. Check the choke operation: Make sure it's working correctly and opening and closing smoothly as the engine warms up.
5. If the problem persists after addressing the above: You may need a professional mechanic to diagnose more complex issues within the fuel or ignition systems. They have the tools and expertise to test components like the fuel pump, ignition coil, and accurately adjust the carburetor.
Remember safety first! Work in a well-ventilated area, disconnect the battery's negative terminal before working on any electrical components, and use proper safety glasses and gloves. If you're not comfortable working on your vehicle yourself, it's best to consult a qualified mechanic.
