I have 2 water pressure guages that just have the small water hose in the back that lead to the sea water pump. The whole time I've owned the boat they both read the same or within a pound or two of each other. Last weekend one started reading about 10lbs. less than the other so I went ahead and rebuilt both pumps just in case that was the problem. Well nothing's changed. This weekend I swapped the lines in back of the guages and presto, one guage is reading low. My question is, has anyone had any luck cleaning out a guage? I know your not supposed to blow compressed air into it but would soaking it in WD40 or some other penatraiting oil help? I must have lodged something in the guage at some point.

Thanks

The line is clogged. Take it off the gauge and the pump and try to backflush with some water or air.

What he said. Blow some air backwards from the gauge end. Turn your regulator down a little. They usually clog up right at the engine end, or shortly thereafter.
Eddie

I don't think the line is clogged. I unhooked the lines on the back of the guages and switched them and the same guage was acting up. That's why I was thinking it was the guage. Maybe it was clogged at one point and the krap or what ever made it's way into the guage?