Pilot's tip of the week

Starting a Flooded Engine


Subscriber question:

"What should I do if my engine becomes flooded during start up?"
- Brendan W.


“Over-priming an engine may prevent it from starting. The presence of a strong fuel smell in the exhaust pipe indicates a flooded condition.

This situation may occur in cold weather when successive attempts to start the engine are unsuccessful. Preheating the engine in cold weather reduces the likelihood of engine flooding.

Look at your POH (Pilot’s Operating Handbook) for the flooded start procedure if the engine won’t start and you suspect flooding. Whether you have a carbureted engine or a fuel injected engine, the general procedure for a flooded start is to move the mixture to idle cutoff and the throttle to wide open while cranking the engine. The idea here is to allow excess fuel to exit the engine through the exhaust. Eventually, when enough fuel clears the cylinders you reach a proper ratio of fuel to air and the engine should begin firing. Once it does, remember to richen the mixture and pull the throttle back for a smooth idle.

Letting the engine sit for a while also helps get rid of excess fuel.

Engine flooding can also set you up for an engine fire during startup. Review your POH for specific procedures for your aircraft for an engine fire during startup so that if it ever happens you will be prepared to respond properly.”

What's your preferred procedure for starting your airplane when flooded?

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