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  1. #1

    Default 2007 8.1 alarm issues. HELP PLEASE

    Have some issues with the motor going into guardian mode. Had the dealer do a scan and said manafolds were getting warm. 130 total hours on motor. salt water use. Do you need to reset it or does it reset automatically?

    Suggested to do the waterpump first and then maybe manafolds. I changed the thermostasts first. No change. Then changed the impeller and the pump housing. No Change. I think I'm going to change the temp sensors next. Question is, what is inside the manafolds that can go wrong? Are there water passages in there that can corrode and cause issues. should I consider doing the manafolds?. Motor runs at about 170 degrees before alarm Goes off. I only have couple weeks left to get this done this season and would like to figure it out before winterizing. Once you let it cool for a minute at idle you will get full throttle back.
    This is a closed cooling system.
    Last edited by NH TOONER; 10-01-2017 at 04:50 PM.

  2. #2
    Join Date
    Jun 2006
    Location
    Spotswood, NJ, USA
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    3,819

    Default Re: 2007 8.1 alarm issues. HELP PLEASE

    with closed cooling 170 is normal .Try using a laser temp gauge or try replacing the water pressure sensor http://www.ebay.com/itm/Water-Pressu...53.m1438.l2649

  3. #3

    Default Re: 2007 8.1 alarm issues. HELP PLEASE

    Quote Originally Posted by Bt Doctur View Post
    with closed cooling 170 is normal .Try using a laser temp gauge or try replacing the water pressure sensor http://www.ebay.com/itm/Water-Pressu...53.m1438.l2649
    Ya it's always run at that temp. Where is the water pressure sensor located?
    going to change both sensors in the manafolds too. Are there any other temp related sensors?

  4. #4
    Join Date
    Jun 2006
    Location
    Spotswood, NJ, USA
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    3,819

    Default Re: 2007 8.1 alarm issues. HELP PLEASE

    either on the power steering cooler or at the raw water pump, let me find the link

  5. #5
    Join Date
    Jun 2006
    Location
    Spotswood, NJ, USA
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    Default Re: 2007 8.1 alarm issues. HELP PLEASE


  6. #6
    Join Date
    Jun 2006
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    Default Re: 2007 8.1 alarm issues. HELP PLEASE


  7. #7
    Join Date
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    Default Re: 2007 8.1 alarm issues. HELP PLEASE

    Manual 30 can be burned also

  8. #8

    Default Re: 2007 8.1 alarm issues. HELP PLEASE

    Thank you
    great info

    What is manual 30?

    can the temp sensors be bypassed or jumped
    for test purposes

  9. #9
    Join Date
    Jun 2006
    Location
    Spotswood, NJ, USA
    Posts
    3,819

    Default Re: 2007 8.1 alarm issues. HELP PLEASE

    30 looks like the mercruiser manual for your motor, You should be able to fool the computer with resistors but I`m still working on the procedure and the values for the sensors

  10. #10

    Default Re: 2007 8.1 alarm issues. HELP PLEASE

    Quote Originally Posted by Bt Doctur View Post
    30 looks like the mercruiser manual for your motor, You should be able to fool the computer with resistors but I`m still working on the procedure and the values for the sensors
    Going to change the exhaust manafolds and both sensors. Also the pressure sensor as you suggest. Where can I get a manual 30?

  11. #11

    Default Re: 2007 8.1 alarm issues. HELP PLEASE

    OK really starting to get frustrated. I changed the water pump housing and impeller. Also the 2 manafolds, both manafold temp sensors and the pressure sensor. Motor does not overheat. Alarm still goes off just over 3000 rpm. I back the throttle off and it goes off. I took the 2 old sensors and plugged them in and put them in a cup of water. still the same thing. Now thinking this is not a water issue. I also changed the thermostat and oil and filter. oil pressure is about 41 . Whet else can make the alarm go off. This is starting to suck and is getting expensive. motor has 130 hours on it. Elbows are stainless steel and look in mint condition Ser# on motor is 0w335279 Also changed the fuel filter and remote water separator.

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