Alcohol In Fuel Testing Procedure

The fuel sample should be drawn from the bottom of the tank so that any water present in the tank will be detected. The sample should be bright and clear. If the sample appears cloudy, or contaminated with water (as indicated by a water layer at the bottom of the sample), this procedure should not be used and the fuel system should be cleaned. Refer to Fuel System Cleaning.

1. Using a 100 ml cylinder with 1 ml graduation marks, fill with fuel to the 90 ml mark.
2. Add 10 ml of water to bring the total fluid volume to 100 ml.
3. Install a stopper.
4. Shake vigorously for 10 to 15 seconds.
5. Carefully loosen the stopper to release the pressure.
6. Install the stopper.
7. Shake vigorously again for 10 to 15 seconds.
8. Put the graduated cylinder on a level surface for approximately 5 minutes in order to allow adequate liquid separation.

If alcohol is present in the fuel, the volume of the lower layer (which would now contain both alcohol and water) will measure more than 10 ml.

For example, if the volume of the lower layer is increased to 15 ml, it will indicate at least 5 percent alcohol in fuel. The actual amount of alcohol may be somewhat more because this procedure does not extract all of the alcohol from the fuel.