Help on prop size?

Discussion in 'Bubba's Outboards' started by riddleofsteel, Apr 29, 2007.

  1. riddleofsteel

    riddleofsteel New Member

    Messages:
    353
    State:
    NC
    Due to an encounter with a large rock I need a new prop.

    The engine is a 2002 Honda four stroke 25 HP.
    BAJS-3221000

    The OEM prop is 9 1/4 x 12.

    Most if not all of the Honda props I see for sale (even from Honda) are at least 10's. The smallest I have found is 9 9/10 x 12.

    I have 5 3/4" between the center of the output spline and the cavatation plate so a 10 seems like it would fit with 3/4" clearance.

    My question is that enough clearance?

    What, if any difference will a 10 as opposed to a 9 1/4 prop make on over all performance?

    Thanks
     
  2. Bobpaul

    Bobpaul New Member

    Messages:
    3,039
    State:
    Supply NC
    More blade surface in the water would mean more power/force to push the boat, that is if your engine can still turn the rpms. More blade surface also puts a slight more strain on the motor, but probably nothing you'd notice.

    You might even get 1 or 2 more mph out of it.
     

  3. JAYNC

    JAYNC Active Member

    Messages:
    1,312
    State:
    Newport N.C.
    my suggestion would be to use the same kind of prop you had if you were happy with it and get a stingray hydrofoil, they are awesome. They get more of your boat out of the water on plane, they plane faster, the boat handles twice as good. IMHO I think outboards should come with them from the factory. I put one on my boat and I got almost 5kts more out of it and its better on gas.
     
  4. Bobpaul

    Bobpaul New Member

    Messages:
    3,039
    State:
    Supply NC
    From the way I'm understanding the original post, is your having trouble finding the original sized prop, and are wondering if a slightly larger prop would work.

    Without any more bs, the answer is YES!
     
  5. riddleofsteel

    riddleofsteel New Member

    Messages:
    353
    State:
    NC
    I bought this engine used from a dealer and it has less than 20 hours on it. I suspect the prop was OEM factory installed but I can not be sure of that. However, when I look at various web sites I do not see a 9-1/4 x 12 prop listed for a 2002 Honda 25 HP. The parts books I can access online seem somewhat vague on the Honda OEM specs.

    Bottom line is that I have 5.75" of clearance between the center of the output shaft and the cavitation plate. Unless I am missing something, somewhere the props I am seeing for this engine vary from 9-9/10 to slightly over 10". I guess if the splines fit and the prop clears the cavitation plate it should work.

    Is there a rule of thumb about how much the prop should clear? I talked to a guy at I-boats.com and he told me to stay within 1/2" of the original prop diameter.

    Anyway I ordered a replacement prop that is 9-9/10 x 12 to replace my 9-1/4 x 12 that I can not seem to find. It should be here by Thursday. If it goes on and clears everything I guess I will try it out. In the meantime I will talk to some local boat and engine dealers about the issue.

    Thanks