I'm traveling and do not have any manuals with me. But the float should freely move up and down when the fuel water seperator is detached and turned upside down. When assembled correctly, the white float will sit on the bottom of the bowl. As the bowl fills up with gasoline (using the primer bulb), the float will stay on or very near the bottom. As water accumulates in the bowl, the float will move up. If it moves up far enough, there is a sufficient voltage drop to set off the alarm. I'm not sure of this, but I thinkif the float is stuck at the very top of the bowl, the engine is not likely to start. At the very least you will get a series of short intermitent beeps from the alarm. Also, make sure that the electrical connections on the bottom of the bowl are secure and clean. If you have access to the Helm shop manual, you can test the sensor for the correct voltages.