J-49755 is used to detect the approximate percentage of alcohol in gasoline.

• Fill bottle with water to indicated line.
• Add fuel to the top line of the bottle from the subject vehicle.
• Cap the bottle tightly.
• Shake the bottle for a few seconds for water to combine with the alcohol.
• After allowing the liquid to settle for about 30 seconds, read the % of alcohol on the scale on the side of the bottle.

Note: Most fuel contains 5-10 % alcohol depending on geographic location and time of year.