Hydraulic helm: lock-to-lock turning ratio too high

Discussion in 'OnBoard Electronics & Controls' started by Vronsky, May 30, 2023.

  1. Vronsky
    Joined: Apr 2014
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    Vronsky Junior Member

    My Mavi Mare hydraulic helm has a 17cc pump and 83cc cilinder ram.
    Turning lock-to-lock should be 4,9, but I'm noticing 5,7 turns
    I read somewhere this could have to do with the (Mavi Mare supplied) hoses expanding: could this explain the almost full turn extra ?
    Mavi Mare says this is due to the integrated non-return and pressure relief valves.
    Does this happen with SeaStar pumps as well ?

    At higher speeds, turning the wheel gets heavy, with even extra resistance during the intitial turn of wheel. System has been bled according to manual, no bubbles coming out.

    Thanks,
    V.
     
  2. Barry
    Joined: Mar 2002
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    Barry Senior Member

    Mavi Mare says this is due to the integrated non-return and pressure relief valves ---- doing what? the pressure relief valves bypassing some of the fluid?

    What is the length of the run from helm to the ram and what type of material is the hose/tubing and the internal diameter of same?

    Do you know what the pressure relief valves are set at?

    How many engines, what horsepower?
     
  3. fallguy
    Joined: Dec 2016
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    fallguy Senior Member

    I've got Seastar and it does what it is supposed to, but I have lines rated for 1500 psi.

    I can't imagine line moving enough to allow that issue.

    The classic sign of air in the line is xtra turns. You have to have a reservoir. Show us a schematic and explain the bleed process. Probably introducing air...can be zero leaks.

    Highly unlikely the xtra turns are related to those internal parts; they might have wanted to get off the call with you and made up a story.

    I have a rather complex twin engine setup and I tried to make it work with a short tube for a reservoir and had to increase the reservoir and I spent like $200 on a bleeder kit..
     
  4. Vronsky
    Joined: Apr 2014
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    Vronsky Junior Member

    Motor is a single 115hp Suzuki, pivots easily when detached from ram.
    Hoses are SAE 100R7 5/16" 190bar (2800psi) about 6mtr each, standard Mavi Mare issue. Pump does 1000psi max.
    No oil reservoir; pump is mounted at 17 degrees angle.
    Don't think the release valve could be adjusted (not in manual).

    System has been bled several times/ways: not a single bubble visible anymore.
    Wheel turns light & smooth when docked/boat not moves, much harder at higher speeds. Perhaps this might have to do with the trim tab: I'll remove and see the effect.

    The almost full extra turn would point to massive amount of trapped air, wouldn't it ?
    No clue where in the system (pump, cilinder, hoses) this could 'hide'.

    THANKS
     
    Last edited: May 31, 2023
  5. baeckmo
    Joined: Jun 2009
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    baeckmo Hydrodynamics

    A picture of the arrangement at the engine side might help; there's something jamming up when the engine is producing thrust.
     
  6. fallguy
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    fallguy Senior Member

    In order to fill the system, you take off a cap off the pump. If you have space; the best way to do the pump fill is with a piece of clear hose and a fitting. The fitting is made with the same threading as the pump and the other side barbed. Then your helm pump can bleed off all air.

    Unless you bleed the system with flow lines; it is unlikely you removed all the air. I checked the Mavi Mare install pages and was not impressed by their lack of detail on bleeding.

    But I also saw this warning which was interesting..seeing as how you may have an affected model.

    My hunch is two problems...one at engine side and/or improper bleeding. But fix all mechanical issues first.

    Take some pictures so those familiar with the Mavi Mare connections for Suzu can see if it is done wrong.

    IMG_0530.png
     
  7. fallguy
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    fallguy Senior Member

    Here is a good link on simple bleeding. I would also go to the engine during this procedure and verify that it turns smoothly through its range (by hand) when the cylinder is open.

     
  8. Vronsky
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    Vronsky Junior Member

    Update: applied the bleeding procedure in the video.
    Lock-t0-lock is now according to spec (5.2 turns).
    Turning of wheel now much smoother.
    I guess there was trapped air in the cilinder, that the manufacturer's bleeding procedure did not remove (or I did not follow accurately).
     
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  9. baeckmo
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    baeckmo Hydrodynamics

    Good to know, thanx for the update!
     
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  10. fallguy
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    fallguy Senior Member

    Honestly, the bleeding procedure as described by the vendor, seemed oversimplified. You have to bleed the system fully and I believe you got trapped into believing it was easier than it is...

    I think one line saying~bleed the system, is easy to under interpret as overly simple!
     
  11. cleancouturellc12
    Joined: Jun 2023
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    cleancouturellc12 New Member

    My hunch is two problems...one at the engine side and/or improper bleeding. But fix all mechanical issues first. I used it for shipping services in Canada and we used it approx ten years.
     
  12. tiiidf
    Joined: Sep 2023
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    tiiidf New Member

    The extra turns on your Mavi Mare hydraulic helm could indeed be due to hose expansion, but it's more likely due to the integrated non-return and pressure relief valves as Mavi Mare suggests. This is less common with SeaStar pumps, which might have different valve designs and tolerances. The increased resistance at higher speeds could be due to additional factors such as fluid viscosity, pump performance, or mechanical resistance in the helm. Ensure the system is properly bled, and consider consulting a professional for further diagnosis.
     
  13. DogCavalry
    Joined: Sep 2019
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    DogCavalry Senior Member

    Something is definitely wrong there if you're feeling resistance. I've a 250ho Evinrude with very similar mechanical advantage, and the control forces are too light for my liking. But then I have the Sea Star system. Maybe something is binding under load, as @fallguy suggested. A 115 isn't a heavy or powerful engine by any means.
     

  14. C. Dog
    Joined: May 2022
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    C. Dog Senior Member

    If hoses rated at that pressure are expanding enough to be noticeable then there is a lot of resistance and an extremely powerful hand operated hydraulic pump.
     
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