Experiments have been conducted to test the hydrogen gas output of a small and portable alkaline electrolyser, a device which converts electricity into hydrogen and oxygen gases via electrolysis process. This cell will be mounted on a vehicle with 12VDC electricity system to supply hydrogen gas to the air intake which will react as a fuel catalyst to enhance combustion and emission while the oxygen will be released back to the atmosphere. The small cell is made of 16 stainless steel plates type SS316 with size of 15 cm x 10 cm x 0.06 cm and the electrolyte is made of distilled water mixed with potassium hydroxide. The aim of this study was to obtain optimal pH level for the electrolyte. Result showed that the hydrogen gas output started to increase when the pH of the electrolyte approached pH14. Almost zero gas production wasrecorded at pH below 13.5. However, by increasing the amount of potassium hydroxide even when the pH was already 14 showed increased amount of gas released. The same result was recorded for distilled water and reverse osmosis water (RO for drinking).