Re: Boat gauges
Ummmm -- don't you think it would help if we knew what type of power plant you had? As in is it an A) I/O which uses an auto engine, is it B) a four stroke outboard or is it C) a two stroke outboard? If you have an auto-based I/O, yes you can use auto based instruments but why would you. They will rust up in a heartbeat since they are not sealed. If you have four stroke outboard you could use an auto oil pressure gauge and possibly an auto tach if the ignition system would support it. If you have a two stroke, the answer is sort of the same but you need to do the math regarding ignition pulse differences between two-stroke and four stroke ignitions. You see, the ignition does not drive a tach on an outboard. The alternator pulses drive the tach. Temp gauges for outboards are calibrated much colder than car based gauges so the needle on a 100 - 260 degree car temp gauge would rarely be off the peg. Gas gauges are not engine related but the fuel sender must match the gauge so again a car based fuel gauge won't work. Voltage is voltage so a voltmeter from a car will work (except for the part about not being sealed).
