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  1. #1
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    Default 2001 Mercury Optimax 135 oil warning horn

    I am getting a warning horn (4-5 beeps) and on my smart gauges it comes up RESERVE Oil Remaining 100%, the percentage drops as I run the boat. When I stop and restart the boat the warning horn (4-5 beeps) and shows RESERVE Oil Remaining 100%. I ran the boat for awhile and the percentage dropped to 71%. We pulled the hood off the motor to check the reservoir and it was full and the main oil tank is also full. When I try to run the motor WOT I get another warning horn - REDUCE THROTTLE. Is this just a bad sensor or more serious? Is it easy to fix or need to take it to a shop?
    Last edited by Walliole0; September 22nd, 2013 at 10:04 PM.

  2. #2
    Petty Officer 1st Class sidenberg's Avatar
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    Default Re: 2001 Mercury Optimax 135 oil warning horn

    Has the oil tank cap on the engine been removed recently to add oil or for any reason? Have you noticed any oil leaking anywhere?
    Has the remote oil tank been filled recently?

  3. #3
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    Default Re: 2001 Mercury Optimax 135 oil warning horn

    Isn't 5 beeps a water seperator alarm saying you have water in the fuel?

  4. #4
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    Default Re: 2001 Mercury Optimax 135 oil warning horn

    THANKS FOR RESPONDING
    I did fill the REMOTE oil tank before going to Canada. Drove it for three days going 15 to 30 miles round trip each day with no problems. On the fourth day we went about 7 miles shut it down and fished. Started it up went about 1/2 mile and alarm started beeping. Not for sure but it would beep 4 or 5 times every couple minutes. The RESERVIOR on the motor was full when we checked it when the smart gauge said it only had 71% oil remaining. The REMOTE tank is down about 1" to 1 1/2".

  5. #5
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    Default Re: 2001 Mercury Optimax 135 oil warning horn

    I did not noticed any oil leaking, will check.
    I did have water in the fuel when I first bought the boat 7 yrs ago and it did sound an alarm, but also showed message on smart guages WATER IN FUEL. Dealer siphoned all the gas out, replaced fuel filter and replaced the fuel that was siphoned out with clean fuel. No problems with that since then.

  6. #6
    Moderator achris's Avatar
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    Default Re: 2001 Mercury Optimax 135 oil warning horn

    The ECU may be doing a calculation based on time and revs, and then coming up with a % left in the tank. That could be if the low oil switch in the reserve tank in the engine is closed (saying low oil).... I would try disconnecting the to switch wires and metering it, or if you don't have a meter handy, just disconnect one of the wires (I would pull the Lt/blue, but it doesn't matter which) and see how it goes...

    If you have a meter handy, with e full tank the switch should be open (∞Ω).... (You don't have to take the switch from the tank to measure it either, just do it in place.)

    Chris.......
    Last edited by achris; September 25th, 2013 at 03:04 AM.

  7. #7
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    Default Re: 2001 Mercury Optimax 135 oil warning horn

    Looked for oil leaks did not find any. I did notice a brass T fitting between the inline oil fiter & the oil reservior on the motor did not have anything on the bottom nipple. Is this normal? It did not look like any oil had been dripping from this. I will meter the switch to see if it is open or cosed.

  8. #8
    Moderator achris's Avatar
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    Default Re: 2001 Mercury Optimax 135 oil warning horn

    Quote Originally Posted by Walliole0 View Post
    Looked for oil leaks did not find any. I did notice a brass T fitting between the inline oil fiter & the oil reservior on the motor did not have anything on the bottom nipple. Is this normal? It did not look like any oil had been dripping from this. I will meter the switch to see if it is open or cosed.
    That's a relief valve, and there shouldn't be anything in the hole...

  9. #9
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    Default Re: 2001 Mercury Optimax 135 oil warning horn

    Switch must be open, did not get a reading from the switch & tank is full.

  10. #10
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    Default Re: 2001 Mercury Optimax 135 oil warning horn

    Well it went to the shop. The oil reservoir on the motor needs replacing. Thanks for the help.

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