Re: Water pressure gauge decision Mercury outboard
I guess the deal with gauges always pointing in the middle of the scale on a boat is rather meaningless unless one is into racing. The tach may be at cruise rpm with an I/O but not with an outboard, the speedometer rarely is, the fuel gauge is only when the tank is half full and that's not accurate either, oil pressure isn't usually at cruise, wot, nor idle, and therefore what use is a 30 PSI gauge when the engine is not capable of putting the needle in the upper half. If the engine is capable of over 15 PSI then this is all moot. Most folks don't look at gauges often enough to notice a sudden drop until the alarm goes off at which point they notice the low/no water pressure. They are more apt to noice subtle drops with each use as the impeller goes bad. I look at the 30 PSI gauge like a 140 or 160 MPH speedometer on most family sedans these days. Pegging the needle is wishful thinking unless you are being pushed by a Corvette, Viper, or a NASCAR Sprint Cup car.