Lawn mower engine outboard motor?

Discussion in 'DIY Marinizing' started by Jeremy Clarkson, Aug 17, 2011.

  1. pistnbroke
    Joined: Jan 2009
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    Location: Noosa.Australia where god kissed the earth.

    pistnbroke I try

    if you look at post 5 you will see that it works fine with a B and S that one was a 3.5 HP but not a bad idea to try it without the blade ...
     
  2. MengWalton
    Joined: Jul 2011
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    Location: United Kingdom

    MengWalton Junior Member

    I haven't reli got a clue when it comes to small engines like these (except model nitro's) But cant you just lay the engine on its side, then there's no need for any 90^o angle transmition.... just a thought

    John
     
  3. Chase_B
    Joined: Aug 2011
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    Chase_B Junior Member

    I believe the "Mud Puppy" uses a horizontal shaft engine with belt drive down to a jet pump,..so scrounge for a jet ski pump and build the "shaft" ( housing for a belt) to the depth you need :)

    just a thought
     
  4. masalai
    Joined: Oct 2007
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    masalai masalai

    I just realised, I have lawn-mower engines on my boat (a pair of Kubota (Nanni sail-drives), same 20hp diesel engine as used on a larger ride-on mower :D :D :eek: :p
     

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  5. Easy Rider
    Joined: Oct 2009
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    Location: NW Washington State USA

    Easy Rider Senior Member

    masalai,

    How is vibration controlled on that type of drive? It would seem that all the vibration of the 2 or 3 cyl diesel would go undiminished right to the bottom of the boat turning it into a big drum.
     
  6. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Eric, I just purchased a 14 HP unit just like the one pictured and it comes with a 'glass box, motor mounts, drive seal, everything. The 'glass box serves to hold the engine and drive assembly, both on rubber mounts. This is bonded in place, after being scribed to fit the hull and a hole cut of course. Once sealed and tabbed in, the box becomes part of the boat (regardless of build method) and the engine/drive assembly can be easily removed.

    It solves a lot of problems and eliminates a lot of parts. No shaft, nor it's alignment, no strut or cutlass, no stuffing box, stern tube, etc. The leak potential is greatly reduced and the motor is a marine based unit designed to live in this tight package, so it has an on board oil pump out setup, filters, heat exchanger, etc. The 14 HP unit was available shipped to me (about 1,000 miles) for less then 9k which is quite reasonable for a nearly ready to install unit.

    [​IMG]
     
  7. masalai
    Joined: Oct 2007
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    Location: cruising, Australia

    masalai masalai

    Thanks Par,
    Well answered and I agree... Some sound does permeate because I have a large resonant surface, (bridge-deck floor), which will be fixed with the installation of a carpet...

    My engines/saildrives came with the OEM kit which included those grp engine/beds, as well as ALL bits to install, including fuel lines, exhaust pipes, ss clamps, wiring harness and right down to a couple of small specialised tools... Au$33K for the pair when the Au$ was about 75cents US.... Not almost the other way round, like it is now at US$1.06... - - PS, those GRP bases are the same for the 2, 3 and 4 cylinder engines as are the legs (I think)? - I am looking for a pair of fixed 3 blade propellers to suit current is 15" x 11" pitch 2 blade folding, suggestions from a) Bob Oram is 3 blade fixed 14" x 13"pitch and from a supplier, 3 blade 15" x 11" pitch on a 17 spline 'shaft'... Any offers/information, please reply on my thread http://www.boatdesign.net/forums/boat-building/my-little-piece-peace-25962-111.html#post483060
     
  8. BATAAN
    Joined: Apr 2010
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    BATAAN Senior Member

    Lawn mower motor without right angle drive.
     

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  9. pistnbroke
    Joined: Jan 2009
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    Location: Noosa.Australia where god kissed the earth.

    pistnbroke I try

    and my version
     

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  10. BATAAN
    Joined: Apr 2010
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    BATAAN Senior Member

    Very nice. Supposedly if some of the prop is out of the water in use, it is more efficient. I think it's called a Surface Piercing Drive and a fellow named Arneson made large modern use of it. A friend described doing 100 mph on the Petaluma river with him years ago.
     

  11. pistnbroke
    Joined: Jan 2009
    Posts: 1,405
    Likes: 33, Points: 48, Legacy Rep: 404
    Location: Noosa.Australia where god kissed the earth.

    pistnbroke I try

    yes but a surface prop has to be designed not just any old prop sticking out the water ....heard of an anti ventilaton plate ( mate )
     
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