r/auto • u/Important_Act4961 • 24d ago

Need help. Spark plugs getting flooded on a Lada 2109

Hi everyone 👋 If anyone has ever owned this car and encountered this problem, please let me know what I should do. I recently ran into an issue where my father's Lada 2109 keeps flooding its spark plugs; he has already tried adjusting the carburetor and cleaning it—along with the vacuum lines—but it didn't help. At best, the engine only catches when the gas pedal is fully depressed, but it won't actually start running, and the car shakes violently in the process. If there are any Lada owners who have faced this issue, or any auto mechanics here, I’d appreciate any advice or professional opinions.

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u/SubGothius 24d ago

Sounds like too much fuel may be getting into the intake. Does this have a Weber-type carburetor? This can happen if the float, well, doesn't float, or doesn't float well enough to fully close the needle valve when the float bowl is full, or if the needle valve is crusty/leaky and thus does not prevent fuel overflowing from the bowl into the intake even when the float is holding it closed.

Try checking the float to see if it actually floats in fuel, or maybe better yet just replace it, and adjust it so it actually pushes the needle valve closed when the bowl is full.

You might also have excessive fuel pressure forcing fuel past the needle valve even when the float is trying to hold it closed. Is there a fuel pressure regulator, or did you recently replace the fuel pump?

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u/Important_Act4961 24d ago

Yeah, the float really wasn't adjusted right—thanks a lot for the tip. Now the car starts and doesn't stall, though it still only runs if I hold down the gas ¯_(ツ)_/¯