how do i build a boat motor with a lawn more engine

Discussion in 'DIY Marinizing' started by jchronister3468, Aug 7, 2005.

  1. jchronister3468
    Joined: Aug 2005
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    jchronister3468 New Member

    hello everyone i need some help. i would like to know an enexspenisve way to buld a boat motor with a lawn mower engine im going put it on a home made 14 ft jon boat any sugggestians would be appreiated with this.thank you jerry
  2. yokebutt
    Joined: Aug 2004
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    yokebutt Boatbuilder


    Most expedient way is probably to graft the engine on to the lower end of a discarded outboard.

  3. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    The most inexpensive way is to get a used outboard. Look into an old SEARS/Ted Williams motor. They had Tecumseh motors. They were also very heavy for the power.
  4. Thunderhead19
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    Thunderhead19 Senior Member

    inexpensive way.....Make a sleeve out of pipe, and use it to add..I dunno say six feet of shaft to the motor. Get a piece of plywood with a hole in it (for the shaft) and mount the motor on it. Put a prop on the end of the shaft, fix the damned thing at an appropriate angle and mount the whole show into a rudder post. Now you have steering and trim. I saw this mostrosity on a documentary on...some...Polanesian..islander fishing ..environmental...something.
  5. Ranger
    Joined: Aug 2005
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    Ranger Junior Member

    Take a look at

    It isn't exactly what you want but you can get an idea from it. In this case, the (horizontal shaft) motor would sit above the transom and the shaft/prop extend well back. The other choice is to run it through a stuffing box and out the underside of the boat. In the first example, you tilt the motor up to start it, then put it in the water. In the second, you have no clutch and you are fighting water resistance in order to start it.

    One problem you never will actually solve is prop angle; it's going to be tilted the best you can do.
  6. lewisboats
    Joined: Oct 2002
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    lewisboats Obsessed Member

    Sounds like a 'Dragontail Motor'. The most likely example that comes to mind is in the Bond movie 'man with the golden gun'. He runs the canals of Bankok I believe.
    Should be an easy build with a horizontal shaft motor.

  7. Bighillwill
    Joined: Oct 2004
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    Bighillwill Junior Member

    If you tilt a vertical shaft mower engine very far, the splasher for the oiling doesn't work right. These engines don't run with actual oil pressure, just a splasher inside the case. running it on a tilt for very long will usually trash your engine.

    If you can find a horizontal shaft motor, like from a rototiller, it would be better.
  8. Thunderhead19
    Joined: Sep 2003
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    Thunderhead19 Senior Member

    .....not to mention the carburetor. The oil situation assumes a "wet sump" motor, ie: a four stroke. I used to have a Lawn Boy mower that had a two stroke "dry sump" motor. It was light and powerfull and had quite a small power head....until I blew it up....
  9. longliner45
    Joined: Dec 2005
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    longliner45 Senior Member

    briggs straton are now making a boat motor with 5 hp 8hp or so .it is a lawn mower engine .they have worked the bugs out .and seem pretty cool probably be just as cheap to buy one new from them. dont know the web site .should be easy to find
  10. george allard
    Joined: Jul 2005
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    george allard Junior Member

    I have seen a lot of boats powered by Briggs and Stratton engines in the Reelfoot Lake area in north west Tennessee. They are all inboard mounts and used in the stumpy lake. They have a protected prop that never hits anything. Search for Reelfoot Lake on the internet.
  11. Richard Hillsid
    Joined: Mar 2006
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    Richard Hillsid Senior Member

    Found this image. War time Finland.

    Attached Files:

  12. Wellydeckhand

    Wellydeckhand Previous Member

    Yahama, Robin and alot other brands sell this prop. Indonesia is graet user of such machine in rivers....... although do not suitable for sea..... beware.

    The engine range from 3 mono- 24 Hp V machine can take from kerosen or gas run water emergency pump. The shaft act as a ratio kit that manage the propellar at the end side.

    Useful but sound terrible as the noise in term of dB would make your nearest neighbour complaint.
  13. Wellydeckhand

    Wellydeckhand Previous Member

    I prefer 2 stroke than 4 stroke because it is lighter but in Thailand I have seen they use small car engine with the pole.............;)

  14. 1ghandi
    Joined: Jul 2006
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    Location: Bendigo,victoria ,Australia

    1ghandi New Member

    You need to set it up like the fishermen a Phuket Thailand do , same design as the Go-Devil , you will need the 2stroke engine about 6hp min also change the carb the LM carbs are too crude , I have bought Mikuni carbs for mine .
    .....................................Cheers Ghandi
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