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Results 1 to 4 of 4
  1. #1

    Post 1999 90hp Johnson

    Purchased boat and had a tough time starting and at low idle. Mid range on up it ran like a top. Mechanic said this particular motor has a Sure Start feature...not sure what that is. He also said each cylinder has a thermostat and one was full of sand and junk. Therefore it was loading up on the low end...which made sense. He pulled something off and let the motor run a bit and the water flushed it clean. It then ran great. It's now acting up again. For starters I didn't know each cylinder has a thermostat, but I would like to flush this out myself to avoid the 100 miles round trip and the $85 to do what the mechanic said I could do. I don't even know where the thermostat(s) are on this beast. Anyone help explain how I can go about flushing the thermostat?

  2. #2
    Join Date
    Aug 2009
    , North Central Iowa,

    Default Re: 1999 90hp Johnson

  3. #3

    Default Re: 1999 90hp Johnson

    It doesn't explain how...but it does at least give me a good idea of where. Thanks!

  4. #4
    Join Date
    Aug 2009
    , North Central Iowa,

    Default Re: 1999 90hp Johnson

    By the looks of it there is a cap on the thermostat, remove the cap and thermostat and start it up and let the water pump flush the system.

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