Mercury waterpressure gauge

Discussion in 'Outboards' started by slow fred, Feb 21, 2011.

  1. slow fred
    Joined: Feb 2011
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    Location: florida

    slow fred Junior Member

    2006, 90 HP, Optimax Mercury. Where do you install, the pressure tube, in the block, for a water pressure gauge?
     
  2. pistnbroke
    Joined: Jan 2009
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    pistnbroke I try

    As I understand it it goes in the pipe which feeds the tell tale ...after all its on the dash to save you looking to see if its piddling ....
     
  3. slow fred
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    slow fred Junior Member

    Do you eliminate the tell tale or put a tee in the line?
     
  4. powerabout
    Joined: Nov 2007
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    powerabout Senior Member

    it all comes as a kit so the correct size tee makes the gauge read but resticting the tell tale but you will hardly notice the difference.
     
  5. pistnbroke
    Joined: Jan 2009
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    Location: Noosa.Australia where god kissed the earth.

    pistnbroke I try

    no you dont eliminate the tell tale as on some engines the flow of water via the tell tale is an integral part of the cooling of the head......you just establish the normal reading at cruise speed and any change from this indicates a problem...you could of course fit a temperature gauge if the head has a 1/8 NPT thread ....google propower in the us they have some 12v ones with as long a wire as you like to the dash gauge
     
  6. slow fred
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    slow fred Junior Member

    Thanks for the help.
     
  7. Frosty

    Frosty Previous Member

    The tell tale has a jet in the end--it is not just an open tube. Therefore a pre determined presure is in the engine and is read by the guage. Where ever the guage was fitted the pressure would be the same.

    The Thais change the pisser so if fires high in the air so it can be seen, most of the time the pisser is at the back and just fires down to the water.

    Guages are good but you got to look at it.
     
  8. pistnbroke
    Joined: Jan 2009
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    pistnbroke I try

    Now frosty come on ..there has to be a pressure difference for the water to move through the engine ..so the pressure at the pump outlet must be higher that at the exit from the block into the exhaust ( and pisser) ....and I thought you were up on technical things .....ha ha
     
  9. Jimboat
    Joined: Feb 2002
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    Jimboat Senior Member

    tee the water line close to the engine block outlet, and take pressure sensor off this tee. The key is know what your "normal" water pressure is, and then to watch it regularly so that any deviation can be an "early warning" notice - before you've done any damage.

    water temp is also a good idea. Temp sensor can be fastened to engine block head bolt or tap location if it exists. Same key as for pressure, know what your "normal" water temperature is, and then to watch it regularly so that any deviation can be an "early warning" notice - before you've done any damage.
     
  10. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    The tell tale also allows the block to drain when the engine stops.
     
  11. Frosty

    Frosty Previous Member




    You like electricity don't you? what you suggested was similar to saying that the voltage at the alternator out post is more than at the batt post or the starter solenoid post.

    Pressure is equal
     
  12. Submarine Tom

    Submarine Tom Previous Member

    If there is no current, amperage, flow, then the voltage will be equal but if there is any current, amperage or flow, then there will be voltage drop through the line depending on the gauge and length of the cable/wire and the voltages will vary at those different points...

    I know, I know, you weren't talking to me, I should probably stay out of it.

    -Tom
     
  13. Frosty

    Frosty Previous Member

    No No thats ok Tom.

    But for this basic argument wire resistance or pipe resistance is not included.
     
  14. pistnbroke
    Joined: Jan 2009
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    pistnbroke I try

    Oh dear Frosty you have put your foot in it ...there has not been a wire invented that did not have resistance or a pipe that did not restrict flow...oh **** what have I dont to frostys reputation ....

    How goes the oil pressure on the diesel engines ???? oops ..****
     

  15. Submarine Tom

    Submarine Tom Previous Member

    So PB, am I to understand you're talking about the miniscule pressure drop through the pipe/tube or is this simply a personal issue between you and Frosty?

    -Tom
     
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