Power Trim Issues

Discussion in 'Engine Questions' started by markbano, Jul 26, 2010.

  1. markbano

    markbano Hydrodyne 18 Specialist

    Joined:
    Nov 4, 2005
    Messages:
    854
    Boat Model and Year:
    1973 Hydrodyne Tournament Skiier
    Hi everyone

    Having a busy summer with the Dyne.

    When I pull my son on the wakeboard I normally trim the motor up to get a bigger wake. Lately, I noticed that the motor will push itself back down despite the trim position when substantial power is applied. This did not used to happen. Obviously, the power trim is not "holding."

    Does anyone know what might be causing this? Could it be low fluid in the trim system? Otherwise, the power trim/tilt seems to work fine.

    Any help would be much appreciated!

    Markbano
     
  2. jim

    jim Hydrodyne 18 Specialist

    Joined:
    Jun 14, 2006
    Messages:
    2,321
    Location:
    FL
    Boat Model and Year:
    77 Dyne 18 I/O converted to Outboard
    Hi Mark,

    Try running the trim all the way up and all the way down several times. That should get the air out.

    If that does not fix it, check the fluid per the manual.

    The next step is some of the internal valves.

    I am betting step one will do it. Mine did the same thing this spring.

    jim
     
  3. jim

    jim Hydrodyne 18 Specialist

    Joined:
    Jun 14, 2006
    Messages:
    2,321
    Location:
    FL
    Boat Model and Year:
    77 Dyne 18 I/O converted to Outboard
    Mark,

    I just spoke to my Mercury Guru. He says that you probably have a leaky o-ring on the up check valve.

    He sends this work to a local hydraulic shop which costs less than a Mercury dealer.

    jim
     
  4. markbano

    markbano Hydrodyne 18 Specialist

    Joined:
    Nov 4, 2005
    Messages:
    854
    Boat Model and Year:
    1973 Hydrodyne Tournament Skiier
    Jim

    Thanks for the tech advice. I seem to remember that I had a couple of drips of hydraulic fluid on the floor below the motor last winter, so it strikes me that you might be right. I will be back up there next weekend and will try the up-down trick. If that doesn't work, then I'll just wait until I bring it home and use a service manual to trouble shoot the problem myself - or, God forbid - maybe I'll take it to the marine dealer for help!

    Thanks again. :D
     

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