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    Hino(39)s-gctid405239

    I have 3888 with hino's 175s they've been good motors but the

    Starboard motor starts overheating at about 2500 rpm and over

    They have 3100 hrs on them, when they to 200 deg. I rev down

    and they cool back down to 160?

    #2
    I'd guess one of 4 things:

    1. Blockage at your thru hull/sea strainer

    2. Bad impeller on your cooling/raw eater pump

    3. Blockage in your heat exchanger/ tube bundle

    4. Blockage in your heat riser elbows.

    Any of these will restrict the flow of cooling water and cause overheating as you increase Rpms

    Darby

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      #3
      Things to check would be both water pump belts, the thru hulls & strainer, no obstructions. The impeller even if replaced recently if you sucked up a plastic bag could be damaged. The trans cooler is clean nothing to obstruct flow like blades off a old impeller. How long since the manicooler & tube bundle was cleaned, has the thermostat been checked? Even the hose to & from the pump could be the cause if the lining has started to separate.
      Capt. Ron.
      "I will not tiptoe through life to arrive safely at death"
      "Never Trade Luck For Skill"
      1987 3870 - Northern Lights ll
      Hino EH700
      Westerbeke 8.0
      1999 Logic Marine 17' CC/50 Merc.
      on Louisiana pool Mississippi River.

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        #4
        Had the same problem on my 250's. tore out both manicoolers, elbows and risers. had them cleaned at a radiator shop, then I put them both back in. total cost for parts (gaskets) and cleaning was about $1500. I agree with the other two posts though, check for blockages first, maybe use a temperature gun, then lasts, clean the manicoolers etc. Not hard to do, but good if you have a friend to help you.

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          #5
          My money is with rrdarby....

          Ken

          Pugetsoundog (woof)

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            #6
            His list is the place to start.

            Simplest is the sea strainer, be sure you have new gaskets for the lid on hand. Mine had been left so long the gaskets would not seal again and I just this weekend had to clean my generator sea strainer and it leaked all the way home until I closed the seacock.

            Then the next simplest is the impeller. If it hasn't been checked for two years you are probably shedding vanes into your cooling system.

            I had only a temp mild rise at 75% load but looked into these things and found both of these things contributing to the problem. Later, I had the elbows changed and though they looked fine from the outside visual check they were in poor shape also being the OEM install on the boat and serving for years.

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              #7
              If you end up pulling cooler for cleaning see post on useing fresh water I never used any water till I pulled them off Roy SE Alaska
              1988 3818
              EH 700
              Custom hard top enclosed

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                #8
                The motel wrote:
                I have 3888 with hino's 175s they've been good motors but the

                Starboard motor starts overheating at about 2500 rpm and over

                They have 3100 hrs on them, when they to 200 deg. I rev down

                and they cool back down to 160?
                My ex3288 did the same thing last year. Cleaned the strainer, opened the seacock with the lid off and water came out of the strainer. Tore apart the sea water pump to check it. Still heated up when running at high rpm. Closed the seacock, disconnected the input of the strainer, Hose clamped a water hose fitting to the hose going to the seacock, hooked it up to the dock water supply. Opened the dock water supply. It built up pressure and then blew out all kinds of sea weed.

                The 32 had the startboard list and squat. The exhaust is always in the water because of the weight of the cockpit cover, 6 batteries, full fuel and water. It's hard to see if losts of cooling water comes out of the exhaust.

                It cost nothing or very little to blow out the thru hull. I would start there fist.

                Comment


                  #9
                  I cleaned the salt side of the maicooler by putting a submersable bilge pump in a bucket of 1:1 ospho and water and circulating it backwards through the bundles until it shopped foaming. It's not serious acid like pool acid but it did the trick. Some pretty ugly stuff came out. Took a few hours and I didn't have to take the manicooler off ($$$ gaskets) or punch holes through the bulkeeads to thread the bundles out in place. Not as good as a radiator shop rod job but it works.

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