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Thread: Tohatsu / mercury 3 cyl water on plugs.

  1. #11
    FFX-61
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    heat them with a map gas torch. hot enuff but not hot enuff to melt alu. yellow can.

    Part one of "Secrets of the OMC Mod 50" : http://www.boatracingfacts.com/forums/showthread.php?t=2052

  2. #12
    Team Member ice_spy's Avatar
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    Is approx 105 psi on all 3 cyclinders too low compression? Could the water in the cyclinders have caused damage that lowered the compression?
    The race never stops

  3. #13
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    could be the gauge, they are all about even, thats what to look for, how do the piston skirts look through the exhaust port?

    Part one of "Secrets of the OMC Mod 50" : http://www.boatracingfacts.com/forums/showthread.php?t=2052

  4. #14
    Team Member ice_spy's Avatar
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    Bore and pistons look ok, no scores or grooves that I can see, only pollished but no cross hatch left. I will post some pics up tomorrow morning.
    The race never stops

  5. #15
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    how much time is on the power head? how fast are you turnin it in rpms?

    Part one of "Secrets of the OMC Mod 50" : http://www.boatracingfacts.com/forums/showthread.php?t=2052

  6. #16
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    Your studs/bolts should be fairly easy to remove since there is so much of the body above the block. My wife likes PB Blaster so use it after heating the bolt and boss. Let sit for a day and try one with heat and a vicegrip. If that doesn't do it try all that again and let sit for another day. Worse case- cut and file, mill if you can, bolt flush with casting surface so you can center punch it, drill and use an easy out. If you screw that up, drill it out and use a threaded insert like a HeliCoil

  7. #17
    Team Member ice_spy's Avatar
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    Cool, thanks for the good advice from all. Slow and steady should win the race. I buggered a head bolt, drilled and tapped a new thread that was off center and basically butchered it. Beyond a helicoil, when I had the block deck skimmed I also go them to center a screw in insert. This saved the my horrible effort to fix in a hurry. So inserts is also another good option if helicoil fails.

    After looking at the pics and my head again, I noticed large amounts of carbon soot that had deposited in the head after last test. Assembled clean both piston tops and head chamber I thought it was strange to have so much deposits. Thinking it was just from the minutes of running. Now I look, I know for sure it is all the carbon and sludge build up inside the exhaust ports that was being sucked clean with water into the combustion chambers. This tells me 100% the water was indeed coming from the exhaust plate side cover gasket failure.
    Hers is some pics of the bore and piston skirts, including the ring and crown area where most overheat often binds around the rings and above. All wear seems normal, no scratches I can feel with my fingernail, no deep grooves or areas that looked excessively worn. Rings feel free and not stuck.
    You can see in one of the pics the very bad misalignment in the intake ports block castings to cyclinder sleeve. Perhaps I should be doing a tear down, new rings and hone and a clean up and port match of the block and sleeve. I know from experience not much is needed to bugger up bottom end performance when messing with ports and grinding. So I would only be doing a clean up really. Small shamfers on the edges is all that is needed from experience with jetski 2 stokes.



    123 top to bottom in order above pics.


    You can see in this last post the amount of 'flushed' out carbon and sludge from inside the exhaust chamber that was the deposits in the head once I removed it.
    The race never stops

  8. #18
    Team Member ice_spy's Avatar
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    Port misalignment pic
    The race never stops

  9. #19
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    Looks like #3 is leaking to me. Look at the gasket ring it has soot on it. Prob pulling water in. Block may not be true.

  10. #20
    Team Member zul8tr's Avatar
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    What brand and type oil and mix are you using?
    " Three may keep a secret if two of them are dead" Ben Franklin
    " ------- well Doctor what have we got a Republic or Monarchy? A Republic he replies if you can keep it"
    Benjamin Franklin, 1787 Constitutional Convention, as recorded by signer James McHenry's in his diary at the Library of Congress

    Location: SW Orlando, Fl

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