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 alcohol contamination is suspected then use the following procedure to test the fuel quality.

1. Using a 3.38 oz. (100 ml) specified cylinder with 0.034 oz. (1 ml) graduation marks, fill the cylinder with fuel to the 3.04 oz. (90 ml) mark.
2. Add 0.34 oz. (10 ml) of water in order to bring the total fluid volume to 3.38 oz. (100 ml) and install a stopper.
3. Shake the cylinder vigorously for 10-15 seconds.
4. Carefully loosen the stopper in order to release the pressure.
5. Re-install the stopper and shake cylinder vigorously again for 10-15 seconds.
6. Put cylinder on a level surface for about 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 be more than 0.34 oz. (10 ml). For example, if the volume of the lower layer is increased to 0.51 oz. (15 ml), this indicates at least 5 percent alcohol in the fuel. The actual amount of alcohol may be somewhat more because this procedure does not extract all of the alcohol from the fuel.