Flooding a gasoline engine happens when the vehicle's carburettor pours too much gasoline into the cylinders. This turns one problem into two problems. Using starting fluid will help the engine to start easily and eliminate the potential for repeated flooding issues. Starting fluid ignites more quickly than gasoline. This means that starting fluid will help the engine to fire and start with a weak spark or other minor mechanical flaw.
Clear the excess gasoline from the engine. In a small engine -- such as lawnmover -- remove the spark plug and turn the engine over a few times with the starter or pull cord. In passenger vehicles, open the bonnet and remove the cover from the breather to expose the carburettor. Use a screwdriver to push down on the butterfly in the carburettor to hold it open. Crank the engine for about 15 seconds with the accelerator on the floor.
Locate the air intake for the carburettor after the flooding issue is resolved. On small engines, this will require removing the cap or lid that covers the intake -- usually located on the upper part of the engine. On passnger vehicles, the air intake is the breather on top of the engine, near the centre.
Spray starting fluid into the air intake. Do not spray more than one or two short bursts. The vapours from the starting fluid will mix with the air as it enters the cylinders to help with the fuel ignition.
Crank the engine a few seconds at a time. For small engines, pull the cord three or four times. If the engine does not start, repeat the process. If the engine does not start after two or three attempts, look for other factors, such as spark problems or fuel-delivery issues.
Always drain the gas from lawnmowers and other small engines when storing them for long periods of time.
Avoid spraying starting fluid directly into the carburettor, as it can cause severe engine damage.