How To Fix Flooded Engine [Easy Tips]

A flooded engine involves your engine receiving too much fuel and not enough air, leading the fuel combination to surpass its upper explosion limit.

If you can’t start your automobile or you notice it cranking very quickly when you turn the key, it could be a result of a flooded engine. 

In this post, you’ll learn what it means to have a flooded engine, what causes it, and how to fix the issue.

how to fix flooded engine

What is a Flooded Engine?

A Flooded engine is simply an internal combustion engine with too much fuel in the cylinder. To burn, the engine requires an appropriate fuel-to-air ratio. Therefore, if the fuel is in excess, the engine will not ignite.

The excessive mixture needs to be cleared before the engine can start. Due to high temperatures, gasoline in the carburetor float chamber may evaporate into the input manifold, causing the air/fuel combination to surpass the upper explosive limit. 

This used to be a common problem with carburetted cars–the engine always drew fuel from the carb into the cylinder, implying that turning the engine over to try to get rid of the extra fuel would draw more fuel in, leaving you with a flooded engine.

However, newer fuel-injected ones are resistant to the issue while operating within standard parameters.

The Symptoms of a Flooded Engine

1. Strong Gasoline Smell 

This symptom is the first sign you will notice if your engine receives more fuel than it can burn. You will perceive a distinct fuel smell when you attempt to start your car.

2. The Engine Won’t Start

Because the spark plugs are unable to ignite the fuel mixture and create power, a flooded engine might make it difficult to start or restart your car.

3. Engine Noise

Your engine makes a quick ‘whirring’ noise when you try to start it, which might indicate a flooded engine.

4. Exhaust color

A darker smoke is another sign that could indicate that your engine is flooded. Because it shows that your engine is burning too much fuel.

Common Causes of Flooded Engine

Faulty Spark Plugs

If your car’s spark plugs are worn out or broken, they will not create an instant strong spark. As a result, the air-fuel combination will not be ignited correctly or at all, resulting in a flooded engine.

2. Excess Fuel

A flooded engine results from too much fuel in the air-fuel mixture. As previously stated, a rich mixture in a car with a carburetor can be produced by faulty or damaged parts or if it is improperly calibrated.

However, it is more complicated with fuel-injected systems. Aside from malfunctioning fuel injectors, additional causes of a flooded engine include bad sensors (O2 sensors, MAF sensors, and so on), a faulty electronic control unit (ECU), and so on.

3. Issues with Other Ignition System Components

Aside from spark plugs, there could be issues with ignition coils, wires, connectors, sensors, distributors, or even the ECU unit.

These result in a weak or non-existent spark, which means the mixture enters the combustion chamber but does not ignite.

4. A Clogged Fuel Injector 

Fuel injectors are responsible for injecting high-pressure fuel into the combustion chamber. They consist of highly durable metal components, and an aggressive substance like fuel sprayed under high pressure will eventually harm them.

When the fuel injector is damaged or clogged, it produces a narrow stream of gasoline causing flooding in the engine.

5. A Faulty Carburetor

The carburetor is a mechanism that combines air and fuel to provide the right mixture for the inner combustion engine.

If the carburetor is malfunctioning (weak or damaged nozzles, damaged gaskets, a punctured float, or something else), it can easily result in an extremely rich mixture and a flooded engine.

How to Fix Flooded Engine

1. Change Spark Plugs

A spark plug plays an important part in your car’s engine. It ignites the air/fuel mixture, causing an explosion that causes your engine to produce power. If your car’s spark plug is soaked with petrol, it won’t be able to deliver enough voltage to start the engine.

Therefore, you need to thoroughly inspect the spark plugs. If you notice this problem with your spark plugs, you must allow them to completely dry out before attempting to start the engine.

If your vehicle does not start after this procedure, you may need to replace your spark plugs.

2. Allow the Fuel Mixture to Drain

Another way to fix a flooded engine is to restore the air-fuel ratio to its normal balance and you can achieve this by letting the fuel evaporate. 

To allow the petrol to evaporate, open your car hood and wait a couple of minutes. You can now try to start the engine after a few minutes. When you restart, do not press the gas pedal, often known as the accelerator.

3. Increase Airflow in the Car Engine

Push the gas pedal or accelerator to the floor and hold it there. Make certain that you do not use the gas pedal at all. To depress the gas pedal, you must first open the throttle and allow air to flow through the engine.

Throughout this process, you must depress the gas pedal for a few seconds. After this, you must wait for a few moments before attempting to start the engine.

You don’t need to do this again if your automobile engine starts, but if it doesn’t, you will need to.

4. Clean the Fuel Injector

A clogged fuel injector could also cause your engine to flood. It is a mechanical device that is controlled electronically. 

The fuel injector’s job is to spray or inject fuel into the engine. If it is dirty or damaged, it can cause a flooded engine. Therefore, you need to clean it before restarting the engine. You must keep cleaning the fuel injector and checking it regularly.

Read: Car Won’t Start When Engine is Hot


A flooded engine is a condition in which your engine receives too much fuel and not enough air, leading the fuel combination to surpass its upper explosion limit.

Whenever this happens, your spark plugs will be unable to ignite the fuel and instead fall out, resulting in a loss of engine power—something you may not notice until the next time you try to start your car.

If the several techniques on how to fix a flooded engine do not work, then it could be that other issues within your engine are keeping your vehicle from starting.

In this case, we recommend you contact a mechanic to help you resolve the issue.