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2001 Luhrs 32 Convertible - Runs hot.

Discussion in 'Luhrs Yacht' started by Thadd, Jun 23, 2021.

  1. Thadd

    Thadd New Member

    Joined:
    Feb 25, 2020
    Messages:
    6
    Location:
    NJ
    Hi. Hoping others with my boat can give me guidance. I have changed almost everything in my cooling system on my 32 and my boat runs hot. I have the marine power 5.7s in the boat. I have addressed the following.
    1. New Risers and manifolds
    2. New intake hoses through the entire system.
    3. Impellars
    4. Exhaust hoses.
    5. Compression check. All good.
    6. Thermostats
    7. Water pumps
    8. Cleaned the heat exchanger. Barnacle busted and soaked closed side.

    Still runs hot when I go above 3500 RPMs. Gets to 200+ And if I run it long it will hit limp mode. Does anyone have this issue? Mechanic believes that the engines are undersized for the boat, but I have a hard time believing it. Hence. I am asking others who own one.

    Thanks.
  2. Thadd

    Thadd New Member

    Joined:
    Feb 25, 2020
    Messages:
    6
    Location:
    NJ
    Sorry. Forgot to mention changed oil coolers too.
  3. Capt J

    Capt J Senior Member

    Joined:
    Jul 11, 2005
    Messages:
    13,930
    Location:
    Fort Lauderdale
    Check for an air leak possible raw water pump sucking air........or collapsed hose while running at cruise.....or a blockage somewhere in the track. Undersized engines has nothing to do with it provided they hit WOT rpm. Do they? Also I think your boat has plates with holes on the bottom, check to make sure they're clear and not all barnacled up.
  4. Joe McKairnes

    Joe McKairnes Member

    Joined:
    Sep 13, 2020
    Messages:
    77
    Location:
    lacey twp NJ
    Was engine work done? Timing off can cause it. What does the water flow at the exhaust look like? If it's strong, points to engine... perhaps even water circulation pump on front of engine...
  5. DOCKMASTER

    DOCKMASTER Senior Member

    Joined:
    Feb 26, 2012
    Messages:
    896
    Location:
    Ketchikan, Alaska
    How long have you owned the boat? Is this a new issue or has it always run hot since you've had it?
  6. Rich Plukas

    Rich Plukas New Member

    Joined:
    Feb 10, 2020
    Messages:
    28
    Location:
    Rochester, NY
    Thadd, somewhat similar problem drove me nuts last year but my problem was at low speeds. I was overheating on one engine and after chasing it for a few weeks we figured out the strainer seal was not working perfectly and it was causing the engine to suck just enough air to impede full water flow. Dogged the lid down clean and tight and problem solved. Worth a check because its simple and cheap. Good luck.