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Overheating Issue

Discussion in 'Ocean Yacht' started by Boomer, Jun 2, 2018.

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  1. cpthawk, Sep 19, 2019
    #161
    cpthawk

    cpthawk New Member

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    Boomer
    Replied to your Flex Flier thread.
    Cheers Capt Joe
  2. Boomer, Sep 19, 2019
    #162
    Boomer

    Boomer Senior Member

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    Received and thank you
  3. cpthawk, Sep 19, 2019
    #163
    cpthawk

    cpthawk New Member

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    If your interested in the J&T boost coolers contact Ron. I think he still knows where to get them. Solved all the summertime cooling issues on our boat.
  4. Boomer, Jul 12, 2020
    #164
    Boomer

    Boomer Senior Member

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    Good morning all...my dreaded overheating issues have resurfaced while at speed...long slow creep for a mile or 2 before I have to pull them back to cool down....I have new raw water hoses, new impeller, heat exchangers boiled out this spring, trans cooler just descaled with barnacle buster, new coolant pump in one motor, coolant good and clean, new t stats, no bubbles in overflow tanks. What am missing? I even dove under the boat with a putty knife to make sure the intake screens were clear
    Last edited: Jul 12, 2020
  5. Boomer, Jul 12, 2020
    #165
    Boomer

    Boomer Senior Member

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    I lost the info for the boost coolers...i am overheating again with these warm gulf temps
  6. chesapeake46, Jul 12, 2020
    #166
    chesapeake46

    chesapeake46 Senior Member

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    Do you have cast iron heat exchangers for the engines ?
  7. Boomer, Jul 12, 2020
    #167
    Boomer

    Boomer Senior Member

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    The tank is cast... the h/e are brass or.something like that
  8. chesapeake46, Jul 12, 2020
    #168
    chesapeake46

    chesapeake46 Senior Member

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    We do not have the temps you do there but the river water does get warm, ( it;s 85* today ).
    I used to have your problem in August when river & bay temps rose & the Rock Fish dove deep for cool water.
    I was assured by J&T and others that my cast iron heat exchangers were fine for my engines. ( only 410 hp 6-71's )
    However:
    My HE's were used in a broad range of horse powers and in the laboratory, they work great.
    In real life over time things are not in laboratory shape.
    I changed my heat exchangers to Lencos in 2007 and have had zero trouble with overheating since
    The lencos will probably not last as long as the cast iron units, this is true but I am ok with that.

    I only put about 100 hrs a year on mine. for reference.
    (No relationship w/ lenco btw.)

    I used to clean out my system with Muriatic Acid when the temps began to climb but had a bad experience with that which helped convince me to loose the cast iron HEs
  9. Capt J, Jul 12, 2020
    #169
    Capt J

    Capt J Senior Member

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    What about your fuel coolers? Is there any place the engines could be sucking a little air? Cracked raw water intake hoses, sea strainer lid gaskets, etc? Is a diver doing a really good job at cleaning your raw water intake screens on the bottom of the boat? What about behind them? Basically I would start at the intakes and follow everything in the path of the raw water.
  10. Boomer, Jul 12, 2020
    #170
    Boomer

    Boomer Senior Member

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    New raw water hoses this year, heat exchangers boiled out in spring, new impeller, oil cooler above shaft acid cleaned with barnacle buster, new circulation pump on one motor...I even use a dab of rtv when fitting the hoses to the hard parts in case I was ducking some air somewhere
  11. Boomer, Jul 12, 2020
    #171
    Boomer

    Boomer Senior Member

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    How do you get behind the screens? No sea strainer tank btw
  12. Capt J, Jul 12, 2020
    #172
    Capt J

    Capt J Senior Member

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    They slide out, you need to be under the boat and a diver.
  13. Capt Ralph, Jul 12, 2020
    #173
    Capt Ralph

    Capt Ralph Senior Member

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    New hoses from the thru hull all the way up?
    Dump cans cleaned?
  14. Boomer, Jul 12, 2020
    #174
    Boomer

    Boomer Senior Member

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    Roger...dont thinks screens have been pulled by a diver
  15. Boomer, Jul 12, 2020
    #175
    Boomer

    Boomer Senior Member

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    New raw hoses sir as you directed last time...I will endoscope the dump cans this week...
  16. Boomer, Jul 12, 2020
    #176
    Boomer

    Boomer Senior Member

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    Someone mentioned thinning the 50/50 coolant to 70/30 with purified water? Thoughts?
  17. Boomer, Jul 12, 2020
    #177
    Boomer

    Boomer Senior Member

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    Boat was fine a few weeks ago when gulf was mid 80s...now that it hit 90, same issue as last summer
  18. Capt Ralph, Jul 12, 2020
    #178
    Capt Ralph

    Capt Ralph Senior Member

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    I usually go the 60/40 or less but this is not your issue.
  19. chesapeake46, Jul 13, 2020
    #179
    chesapeake46

    chesapeake46 Senior Member

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    Before I replaced my cast iron HE, I tried distilled water and Nalcool which is supposed to dissipate heat better than anti freeze.

    It did not help my situation.

    Had to replace the antifreeze in the fall here of course.
  20. cpthawk, Jul 13, 2020
    #180
    cpthawk

    cpthawk New Member

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    i believe these boost coolers were made for J&T by sen-sure marine in Lauderdale. these were installed on the boat in 2000, no more heating issues. they replace that cross feed pipe that's been discontinued.
    boosttop.jpeg boost2.jpeg
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