How to Fix a Flooded Lawn Mower

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A common problem with gasoline engines, whether automobile, snowmobile, or lawn mower, is that they can become flooded. This usually means the carburetor has become overloaded with gasoline and is not able to get enough air. When flooding occurs, the only way to get the engine running again is to normalize the gas-air mixture. With a lawn mower, this flooding can be caused when you give the primer button too many pumps. Or, it can be caused by a gas-saturated air filter. Here are 5 steps you can use to restore that balance.

Step 1 - Test the Engine for Flooding

Before committing yourself to the time it will take to manually remove gas from a saturated filter, you will be wise to do a test that will tell you whether or not the mower's starting problem is cause by flooding or something else.

2 - Remove the Gas Filter

Locate the mower's filter box, usually a plastic box about 4" to 5" square. When you have found it, remove it's cover which will normally be kept in place with a single screw. You can easily remove this screw with a screwdriver. Then, remove box cover. Inside, you'll find the filter, sitting unattached in the box. The filter will typically be composed of paper, sponge, or a cloth-like material. When you remove the filter you will be able to feel or see whether or not the filter is saturated with gasoline. If it is, chances are good that failure of the mower to start was due to flooding of its engine.

Step 3 - Allow the Filter to Dry by itself

If you wait long enough--usually an hour or longer--the gasoline will have evaporated from the filter and will allow air to again enter the engine's combustion chamber. Drying time will vary according to outside air temperature and humidity. Ultimately, if you wait long enough, the filter will dry out and you will be able to start the engine, using normal starting procedures.

Step 4 - Speed Up the Evaporation Process

Should you decide not to wait for normal evaporation to fix the problem, you can speed up the evaporation process by exposing the filter to sun and air. Just leave the cover off and wait for the fuel to evaporate.

Step 5 -  Do a Manual Fix

An optional way to fix the flooding problem will be to manually remove the fuel from the filter. To do this, you must first remove the filter from its compartment. The filter will be composed of a heavy and porous paper, sponge, metal mesh, or a material that resembles cloth. If your filter is the paper variety, you will need to be careful in handling it. Otherwise, it is likely to disintegrate. Other filter materials will not be as fragile as the paper type, and you will be able to squeeze them and force out any gas the material contains.

Once fuel has been removed from the saturated filter, replace the filter and its cover, and you should be able to start your mower with no trouble. 

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