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motor height

lckirklckirk Posts: 87 Greenhorn
Just seeing what anybody thinks. I am wondering if my motor is mounted to high. My time to plane sucks, I have a Vengeance 15 pitch on a mercury 115 efi The boat is a 19ft bay boat. I have tried a Vengeance 14 pitch and it was not any better. Just looking for some advice and buying a new boat or motor is not an option.haha

Replies

  • gandrfabgandrfab Posts: 21,646 AG
    1st question have someone drive it wide open on flat water for you.
    Then hang your head over the trans, the anti ventilation plate should be at the waters surface.
    It looks low now.
    Next if you are having a problem getting up on plane drop the pitch and or go 4 blade.

    Stuff to test, we can talk about tricks to getting on plane in shallow water after you have that worked out.
  • 1outlaw1outlaw Naples FLPosts: 1,774 Captain
    Does the motor bog when you attempt to plane off?
    Looks like the motor is low to me.
    Jason :USA
  • lckirklckirk Posts: 87 Greenhorn
    Thanks for the info.
  • lckirklckirk Posts: 87 Greenhorn
    It does not bog dow.
  • squidvicioussquidvicious Posts: 537 Officer
    gandrfab wrote: »
    1st question have someone drive it wide open on flat water for you.
    Then hang your head over the trans, the anti ventilation plate should be at the waters surface.
    It looks low now.
    Next if you are having a problem getting up on plane drop the pitch and or go 4 blade.

    Stuff to test, we can talk about tricks to getting on plane in shallow water after you have that worked out.


    before we start dropping pitch - you need to find out what RPM the motor runs @ wide open throttle


    if RPM is low,odds are,the prop's pitch is too much

    4 blade,in the same pitch,will actually cause time to plane to increase,also drop RPM - due to more "blade surface"


    all this applies to a motor,with known good health...



    motor looks a few holes low...
    can we please stop using the word ISSUE ? it's a PROBLEM
    :wink
  • FS DanFS Dan Posts: 2,353 Moderator
    Trim the engine to zero trim. place a straight edge on the bottom to the hull and see where the cav plate is in relation to this edge. The general rule is that for every 12 inches of engine setback from the boats trailing edge. You can come up 1 inch with the motor height.
    so a 1/4" every 3" of set back. In your case the cav plate should come about a half inch above your straight edge. The bolt holes are in 3/4" increments. Do the rpm test as mentioned before.
    your other option could be trying one of the vented props. Underpowered or heavy vessels benefit from a vented prop, because the venting allows the prop to spin more rpms during holeshot. The higher rpms allow the engine to get into the top of its power band.

    FSD
    Formerly Catmandew
  • gandrfabgandrfab Posts: 21,646 AG
    Side note
    Even the same hulls run different with different loads and uses.
    That is why we have trial and error.
    I Had a tach on my 17' skiff and had 5 different props on it before I found the one I liked.
    If I move the weight forward on the boat I could over rev it and get 2 more mph.
  • lckirklckirk Posts: 87 Greenhorn
    before we start dropping pitch - you need to find out what RPM the motor runs @ wide open throttle


    if RPM is low,odds are,the prop's pitch is too much

    4 blade,in the same pitch,will actually cause time to plane to increase,also drop RPM - due to more "blade surface"


    all this applies to a motor,with known good health...



    motor looks a few holes low...
    I run about 5800 to 5900 WOT.
  • lckirklckirk Posts: 87 Greenhorn
    FS DAN I am going to line it up tomorrow with a straight edge and see what it looks like. Thanks everyone for the advise.
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