User Tag List

Thanks Thanks:  0
Likes Likes:  0
Results 1 to 4 of 4
  1. #1
    Join Date
    Jun 2016
    Location
    ORILLIA, ONTARIO
    Posts
    2
    Thanks (Given)
    0
    Thanks (Received)
    0
    Likes (Given)
    0
    Likes (Received)
    0
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    135 hp OPTIMAX overheating

    Hi all.
    2003 135 OPTIMAX, 375 hours, pushing a 18' Boston Whaler. I'm getting high temp when running at low speeds (up to 175 degrees,@ 1500 RPM)

    @ 1700 it drops to 120.
    Two thermos today didn't change a thing. New impeller last fall.
    Any good thoughts???????

  2. #2
    Join Date
    Jun 2009
    Location
    central minnesota
    Posts
    770
    Thanks (Given)
    6
    Thanks (Received)
    30
    Likes (Given)
    5
    Likes (Received)
    24
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    use temp gun and narrow it down,l/r head or air pump?just impeller?after market pump?pinch a waterpump grommet?drop case inspect pump-th

  3. #3
    Join Date
    Jun 2016
    Location
    ORILLIA, ONTARIO
    Posts
    2
    Thanks (Given)
    0
    Thanks (Received)
    0
    Likes (Given)
    0
    Likes (Received)
    0
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    OK
    I'll start checking those out

  4. #4
    Join Date
    Feb 2004
    Location
    North Tonawanda, NY
    Posts
    686
    Thanks (Given)
    0
    Thanks (Received)
    8
    Likes (Given)
    0
    Likes (Received)
    23
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    If the engine cools down quickly when above 1600 rpm or so that's the poppet valve opening- so your high speed cooling system is OK. Overheating below 1600 rpm or so is usually caused by one of three things on an Opti. First is a bad impeller- or bad install on a replacement. Pressure at idle speed should be at least 1.5 psi on a new impeller(Opti's have a very low pressure cooling system at idle), and at least 1 psi on an old impeller. Second thing is failed thermostats- from clogging with dirt/weeds/etc. These are simple to just replace since it's a pain to blow them out and test them. Third thing is a clogged intake screen on the coolant hose going into the air compressor. Typically you have to drop the lower cowl to get to the fitting, which is close to the compressor housing.
    Doug

Similar Threads

  1. Optimax High RPM Overheating
    By Salty Dog in forum Four Stroke and Direct Injected Two Stroke Engines
    Replies: 6
    Last Post: 11-27-2013, 10:01 AM
  2. 2.4 175 overheating
    By XTB21 in forum Technical Discussion
    Replies: 73
    Last Post: 12-19-2012, 08:00 PM
  3. 225 overheating
    By Quick Rick in forum Technical Discussion
    Replies: 2
    Last Post: 07-07-2006, 04:02 PM
  4. Overheating...Help!!!!!
    By samann in forum Technical Discussion
    Replies: 1
    Last Post: 07-28-2004, 10:29 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •