What is the reason for no fuel coming out when unscrewing below the carburetor?
4 Answers
Reasons for no fuel coming out when unscrewing below the carburetor are as follows: Excessively lean combustible mixture: The carburetor backfire phenomenon is caused by the combustion flame returning from the intake pipe to the carburetor after the spark plug ignites the mixture, which is attributed to an excessively lean combustible mixture. Carburetor backfire: The mixture becomes so lean that the combustion speed is too slow. The time from the start of mixture combustion to its completion extends until the beginning of the next cycle's intake stroke when the intake valve opens, igniting the mixture in the intake pipe and causing carburetor backfire. Intake valve malfunction: The intake valve is stuck in the open position and cannot close. Reasons for valve sticking include scoring of the valve guide, bending of the valve stem, or loosening of the valve seat, all of which prevent the intake valve from closing properly. The spark plug ignites the mixture, which then ignites the mixture in the intake pipe, leading to carburetor backfire, and the intake valve being stuck open, resulting in incomplete closure.
I've been driving old cars for over a decade and have encountered situations where no fuel flows out when opening the carburetor quite often. This is usually due to fuel line blockages or fuel tank issues. First, check if there's still fuel in the tank—if it's empty, where would the flow come from? If the tank is full, then inspect the fuel lines for any damage, aging, or air leaks, as blocked pipes won't let fuel through. The filter is also crucial; a dirty one can block the fuel. If all these are normal, the problem typically lies inside the carburetor—the float might be stuck, the needle valve could be clogged with dirt or worn out and unable to close, preventing fuel from entering the float chamber. Additionally, if the fuel pump is faulty and not creating suction, it won't be able to draw fuel. This isn't something to handle carelessly; gasoline splashing when opened can easily cause a fire. I recommend parking the car and having a professional mechanic handle it rather than forcing a fix yourself. Regularly cleaning the entire fuel supply system can prevent such headaches, keeping the car in good condition for worry-free long-distance drives.
Bro, I reckon it's most likely a fuel line blockage. Check if the fuel tank is empty—no one can do anything with an empty tank. If there's fuel, the pipe might be clogged with rust or debris, causing a vacuum leak and preventing fuel from being drawn up. The filter is also crucial; if it's packed with dirt, it'll disrupt fuel flow. If it's a carburetor issue, the internal float might be stuck on one side, blocking fuel entry. A faulty needle valve can also cut off fuel supply. A weak fuel pump with insufficient suction is another common culprit. Make sure the engine cools down before working on it to avoid accidents. My old car had the same problem last time—turned out to be sludge buildup at the tank bottom. Replacing the fuel filter fixed it. Regular maintenance saves a lot of hassle.
There may be an issue with the fuel supply system: the fuel tank is empty or clogged with excessive impurities blocking the pipes; aging, cracked, or unsealed fuel lines causing failure to draw fuel; a dirty filter obstructing fuel flow; a stuck float inside the carburetor preventing normal opening/closing or a clogged needle valve malfunction; or a failed fuel pump lacking suction to draw fuel. It is recommended to park the vehicle and first check the fuel level in the tank and the condition of the fuel lines. If everything appears normal, remove the filter to inspect its condition, or directly consult a professional technician for a thorough inspection to ensure safety.
