My outboard is spraying water at me

Discussion in 'Propulsion' started by stonedpirate, Nov 21, 2014.

  1. stonedpirate
    Joined: Nov 2009
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    Location: Australia

    stonedpirate Senior Member

    Hi all

    I just bought my first power boat and have a small issue with it.

    Its a stacer rampage 429 http://www.stacer.com.au/Aluminium-Boat … %20Rampage

    With yamaha 30hp 2stroke.

    The first time i went out with 2 women on the front seat and me on the back and didnt notice any back spray. This morning when i took it out alone, i noticed that i had a lot of vertical spray as soon as i planed.

    Some spray gets in the boat.

    I moved the tilt bar up one hole and this made the spray much worse and started overflowing water into the boat over the transom.

    My guess is that the yammy long shaft is too deep in the water?

    Is there a way to raise outboard of the 2 clamp type?

    Or is it another issue?

    I have no transducer or any other attachments, completely stock.

    Thanks
     
  2. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    I would keep the women and forget about adjusting the motor;). Check the anti-ventilation plate. The bottom of it should be about 4-8mm above the keel. You can use a piece of board or anything straight to check it.
     
  3. stonedpirate
    Joined: Nov 2009
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    stonedpirate Senior Member

    Haha

    Will do, cheers
     
  4. stonedpirate
    Joined: Nov 2009
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    stonedpirate Senior Member

    Here is a little video i took with my phone of the spray.



    Here is the ventilation plate relative to the hull:

    [​IMG]

    As you can see, it is a fair bit lower than the keel. My question is, why would stacer make a transom for long shaft motors that are clearly too low? The dealers mainly package these boats with long shaft 30 yammys and suzuki 30s. Both are around 550mm in transom length.

    [​IMG]

    Is it a bad idea to put a block of wood under the mount on top of the transom and clamp near the lip of the transom? Or will that cause the engine to fall off?

    Any other way i can raise this outboard?

    Thanks
     
  5. Mr Efficiency
    Joined: Oct 2010
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    Mr Efficiency Senior Member

    It is usual for the anti-ventilation plate to be at the same level as the lowest projecting point of the hull, which in this case would be a keel extrusion. Any lower than that is too low, much higher and you risk interference from that keel/skeg ahead of the propellor.
     
  6. whitepointer23

    whitepointer23 Previous Member

    Looks like a 16 inch transom with a 20 inch leg. Measure the depth of the cut out on top. I bet it is 5 inchs. You could take it to a boat place and get them to weld a filler in the top. If it left the boat dealer like this they should be paying the bill.
     
  7. stonedpirate
    Joined: Nov 2009
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    Location: Australia

    stonedpirate Senior Member

    Thanks guys

    I just measured the cut out section and it was 5".

    The anti-ventialtion plate is 1.5" lower than the lowest hull extrusion. It needs to be raised by 4cm but there is only 3cm of space left on the transom for it to move.

    I will put a 3cm block of wood under the outboard and see how it goes.
     
  8. stonedpirate
    Joined: Nov 2009
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    stonedpirate Senior Member

    I think i figured it out.

    The transom is 20".

    The yamaha cv30 has shaft length of 21.7".

    The extra 1.7" is coming from the out board.

    Can only raise it just over an inch so will have to live with 0.6" under the hull.
     
  9. stonedpirate
    Joined: Nov 2009
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    stonedpirate Senior Member

    Final question, will clamping the outboard to the very top of the transom hurt the transom or cause the engine to fall off?
     
  10. rxcomposite
    Joined: Jan 2005
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    rxcomposite Senior Member

    The engine might fall off. There will be very little grip on the transom. Check the outboard mounting instructions. It says the the ventilation plate is about 3/4" (20 mm) below the base of the hull. Since it is not exactly at the lowest base (deadrise intersection) you have to experiment.
     
  11. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    You should measure from the upper part of the curved bottom, not the keel edge. The water will flow from the highest point. You could screw an extension to the top of the transom.
     
  12. waikikin
    Joined: Jan 2006
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    waikikin Senior Member

    You could do that..... if the clamp is still below the lip- for it to fall off the clamps must first slip= too loose...... also you need a lanyard for the motor, thats what the ring is for- tie it to the transom brace.
    Or get an extension on the transom height, some motors also have the option for bolts.
    Jeff
     
  13. whitepointer23

    whitepointer23 Previous Member

    You have to move the engine up a few inchs. Look at the top of the piece of wood in your photo. That should be about in line with the bottom of the drain bung.
     
  14. stonedpirate
    Joined: Nov 2009
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    stonedpirate Senior Member

    This sux.

    Remeasured the transom minus the keel and its 18.5" with a 21.7" outboard shaft.

    This is such a common hull and motor combo in my country, really makes me wonder lol.
     

  15. stonedpirate
    Joined: Nov 2009
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    stonedpirate Senior Member

    The bolt holes allow for 2.5" raise so i will go ahead and bolt it on.
     
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