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Unidentified Dials

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    Does anyone know what these are for (see attached picture) ? I’ve always assumed one is the engine oil pressure, but not sure why there would be two. The numeric dial also seems to serve no purpose ?



    David Babsky

    Going from memory – as I’m not on the boat just now – the left-hand one (with greater range, up to 150 psi, is the ENGINE OIL pressure gauge, and the right-hand one should be the GEARBOX OIL pressure gauge.

    I’ve marked mine with a little white chinagraph-pencil mark on the black surround at the optimum pressure readings, so that I can see at a glance if all’s well (..or if oil’s well). Ditto with the temperature gauge that I can see if the engine’s getting anywhere near its 99-degree TOO HOT mark.

    (..And I ALWAYS check the oil level of both the engine AND the gearbox before setting off anywhere Dover, the other year, I found that the gearbox was full of margarine: cracked gearbox oil cooler, so I had it replaced by those very nice engineering men just outside the marina gates, having replaced our ENGINE OIL cooler a year or two before. Now they should both last another 30 years.)

    (..Wow, this great on white is almost impossible to read while I’m typing!..)

    Yours, David.

    David Babsky

    P.S: The upper scale is units in PSI (pounds per square inch), and the scale beneath that is the same thing but in ‘bar’ vehicle tyre-pressure scales.


    Thanks David.

    Alasdair Woodfield

    Hi Richard,

    Engine oil pressure, and temperature.

    The 3rd ?? How about hydraulic steering, water pressure, or perhaps ‘steam pressure’ when the skipper ‘loses it’ !?? The two pressure gauges have different scales, I don’t think engine oil pressure would go to 10Bar without something going bang. On my 331 the 3rd gauge is engine revs.

    I guess the answer lies in tracing the wiring/tubing back to a sensor ?




    Think the third one may be oil/ coolant temperature , usually around 90 centrigade after warming up. The sensor is in the water side, but really monitors all the engine fluids. If you suspect the impellor has lost a vane, that’s the gauge that will give you a clue, stop the engine before it boils the coolant

    Gordon Paterson

    On my boat (Nauticat 40) I have two gauges one shows engine oil pressure the othe shows gearbox pressure as it is a hydraulic box.

    Graham – I thought that you no longer had a Nauticat?



    I agree, engine oil pressure and gearbox oil pressure

    Mark Ashley-Miller

    Just to add – engine temp gauge (the bottom dial I guess) – I inadvertently ran my engine at 3500 rpm for 30 minutes recently and it went well over 100C – as soon as I dropped reves below 3000 it came back down to 80/90. No damage done I hope!


    Just adding on here. On my NC33 the gauges represent Engine Oil Pressure, Gearbox oil pressure and engine coolant temperature. The reference to “bar” is the alternative pressure units (like bars or barometric pressure)


    On my N38 with a Ford Lehman 80 its the other way around.
    The left is Gearbox oil pressure and the right one is the engine oil pressure.
    According to the Nauticat manual the normal engine oil pressure is between 50-57 PSI and
    the normal gearbox pressure is 106-136 PSI. So it makes sense that the left is gearbox oil because the right one can’t show the high gearbox pressure.

    Ingvar in Sweden

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