Weed eater engine conversion

Discussion in 'DIY Marinizing' started by Ward, Jun 2, 2003.

  1. Rangerspeedboat
    Joined: Apr 2009
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    Location: Texas

    Rangerspeedboat Senior Member

    What you say may be true but Wave whacker is talking about long term use, meaning something his grand kids can use when they are old enough to have grand kids. It is nearly impossible to kill a briggs motor I have an old briggs powered reel type mower and it starts on the 2nd pull every time.

    I built a one of these out of a ryobi a few years back, it worked but it was difficult to start, didn't run right and too under powered, and I'm a guy who can get any small engine to run perfectly.

    I'm not saying they don't work, I'm just saying that for the time and effort I would put into building one of these I would much rather use a small briggs motor.
     
  2. Mark Wo
    Joined: Dec 2007
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    Location: Minnesota

    Mark Wo Senior Member

    What I'm saying IS true. You too are implying we don't know what we are talking about. I guess I missed the part about being able to pass this along to Wave Whackers grandkids. Maybe you could point it out to me exactly where he said this.

    When you've been dealing with people for 3 or more years who say these things don't work, and who have NEVER built one or run it, it truly blows me away. Think this whole post that has been around for years would exist if these motors didn't work?

    Also, if you've read the entire post, you would see where many, including me, have said the Ryobi 31 cc motor does not work well. I know Turn 4 Fun has made them and had success and I wish I knew how he did so. I've built one and I couldn't get it to run well and I knew it wouldn't last. You could smell the clutch everytime this motor was placed into the water.

    Because of this, I found a 51 cc motor from Duropower that worked very well. I still have this motor, going on its third season, and it still runs well.

    I tend to listed to people who have built these things and had success rather than listening to those who have never built one but claim they will never work.

    Mark
     
  3. wardd
    Joined: Apr 2009
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    Location: usa

    wardd Senior Member

    get a vacuum pump from an auto store put oil in the jar with the bearing and pull a vacuum and wait till the bubbles stop rising and release the vacuum and air pressure will help force the oil in

    repeat,,,,,,
     
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  4. notsofast
    Joined: Nov 2009
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    Location: Philippines

    notsofast Junior Member

    I used 4 pcs bamboo busings. Works just fine while bathed in motor oil. No burnt bushings after 2 hours continuous running. :)

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  5. Wavewacker
    Joined: Aug 2010
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    Location: Springfield, Mo.

    Wavewacker Senior Member

    Mark, you must have a good little engine and I'm glad it works for you around that farm pond, (LOL) but I doubt it would get me up the Mississippi with a 4' chop or glassy and try to cross in some areas with the current.
    I guess my thinking is more toward larger boats, not 10' ers, but the OP did say a 12' er, but guess that would work. I can't even get my yard trimmed with one tank of gas (the tank that is on it, BTW). Obviously I have the wrong trimmer. I wouldn't venture out with such a rig without spare recoil parts. Not to say they don't work, just to the economical side of things, IMO, you'd be better off with a heavier engine, like an old Briggs or a chain saw engine, about 5hp or more.

    Glad your rig works for ya....:D
     
  6. Mark Wo
    Joined: Dec 2007
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    Location: Minnesota

    Mark Wo Senior Member

    Check out the Honda GX35

    Good little 4 stroke mini's. Run forever, very quiet, built tough.

    Farm pond - hardly. I travel a couple of miles each way on a couple of streams I hunt and my small boat is 15' but only weighs 60lbs. I used to paddle but then I got older and lazier. I sought another way to still hunt these places but make it easier. Thus the mini mud motor. If you are building this type of motor to hunt 4' chop on the Mississippi, you're nuts. That's why I have the bigger boat with the bigger motor. I've used mine to go 1.5 miles upstream to hunt a nice little spot on the Mississippi but it is protected waters and I have to haul my boat/equipment over a 4' embankment to get to the honey hole. No way my little boat would be stable for the water you mention.

    I built my motor for my small boat to hunt small streams and small lakes. Weight was everything as I have to carry in everything I need to hunt when I go to these places. A mud motor that starts out weighing 60 plus pounds is not going to work. Depending upon which motor I use, they all weigh less than 20 lbs. That extra 40 pounds makes a world of difference when hauling my stuff around .

    When this motor goes bad, they are so common I can buy a replacement for around $220. Not bad. What's that Brigss and Stratton cost to replace?

    These motors have their place and thus the reason many of us set about to build them several years back. I still get emails from people who have never built one nor seen one in action telling me how it will never work. Usually I ignore it but on this thread, it should be very easy to see that they do indeed work and work well.

    Mark
     
  7. Erich_870
    Joined: Feb 2009
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    Location: Juneau, Alaska

    Erich_870 Junior Member

    Mark's right on with everything he said. It's really easy for guys to come along and make WAG's about whether it will or won't work, but never try it themselves.

    Duck hunters by our very nature have pushed the evolution of this idea to the point we are right now. We hunt from small boats, just big enough for a guy, some decoys and gear, maybe a dog. The boat needs to be small to hide well, so if you want to put a motor on it, it also needs to be small and light with a high power to weight ratio. Every new person seems to come along and say, "just put a trolling motor on it!". That's a great idea until you look at how much a battery weighs and how long they keep a charge on cold, wet days. When you come from the other side, the stock gas outboard, you find that they are designed for larger boats, even the little ones require a transom that tends to be too tall or they’re water cooled so the marshes we hunt will plug them up. A small 4 stroke weed whacker engine is a very good compromise to make a motor that is light, powerful and has a long run time on a tank of gas.

    Your chainsaw suggestion is valid. They have very high power to weight ratios. I'd use one in a boat motor if I had one to tear apart. There are people out there using them to power bicycles too.

    Erich
     
  8. Mark Wo
    Joined: Dec 2007
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    Location: Minnesota

    Mark Wo Senior Member

    Yep

    Electric motors don't work because of the batteries and even more so, they require a certain depth of water to run. My mud motor can go in as little as 6" of water under the keel. An electric can't do that. The other problem with the electric, and small outboards, is that when you come to a spot where you have to get out and walk due to shallowness, you have to tilt the motor. Try doing this a dozen or so times traveling up or down a small stream and you soon realize that these motors are not the way to go.

    I love these litte workhorses as they have gotten me into spots that no one else can get to. I can find places to hunt 20 minutes from my house (and I live in a metro area of a few million people) and not be around anyone. What a treat. Several of my hunting buddies, who have yet to see the light on the small boat/small motor package, will travel upwards of 4 hours to get the similar experience and shoot no more ducks than I do. in most instances, I outshoot them.

    Here is a pic of a couple of these spots. They are each two miles or more from a small walk in landing for canoes. Downstream. Can't get a big boat back there, it is private land on each side of the river bank getting to this spot, and when the water freezes everywhere around on the bigger bodies of water, these types of places are deadly. After a morning of hunting in near or below zero weather, that thought of paddling back upstream two miles or more is a horrible thought. I used to do it. Almost gave up late season hunting because of this paddling. Built a mini mud motor from what I learned elsewhere and added my own twists and these spots are now a couple of my easier late season hunting places to get to.

    Mark
     

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  9. edvb
    Joined: Mar 2008
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    Location: Oshkosh,WI

    edvb Junior Member

    Hi all

    First post here.

    I have a outrigger sailing canoe that is the same size as a Hobie 16. It weighs 160 Lbs and want a rig to get me out of the channel that is about a 1/2 mile long. I need the most lightweight rig possible .It will be mounted on the rear beam. Everything is carbon so I want to keep it as light as possible.

    I can paddle at 2.5 Knots all day ( ZRE Outriggger paddle ) and this is what I want to achieve.
    The rear beam is about 21" off the water.

    Noise is a big factor so I want to be able to run the exhaust below water in the down position.


    90 Degrees from up to down.

    Hope you can all help.
     
  10. edvb
    Joined: Mar 2008
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    Location: Oshkosh,WI

    edvb Junior Member

    [​IMG]

    [​IMG]

    It will go in the corner between the cot crossbeam and the curved traveler.

    Just to the right of the curved mast holder on the left side of the picture.
     
  11. edvb
    Joined: Mar 2008
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    Location: Oshkosh,WI

    edvb Junior Member

    The system has to be dropped from 20" above the water line and not extend more than 60" to the rear.

    Direct drive seem's best. Info on best components today would help.

    Thanks for any help on this. The lighter the better.
     
  12. pistnbroke
    Joined: Jan 2009
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    Location: Noosa.Australia where god kissed the earth.

    pistnbroke I try

    ed get your self a small 2-3 hp outboard ..you will find many second hand and look for a 20 or 25 in leg often called a sail drive ..or use a bracket that goes up and down if you cannont get a 25 in leg ..spend your time getting the OB running good rather than building a noisy buzz box on the back
     
  13. docott
    Joined: Feb 2012
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    Location: Louisiana

    docott Junior Member

    "Coupler"?

    Hello. I've really enjoyed this thread. Lots of innovative ideas to build on. I've read through the entire thread twice. I have a few questions, but I'll start with this one:
    How do I connect/couple the tube (in which the drive shaft resides) to the engine? I understand that this is simply done by attaching it to bottom part of a string trimmer I place of the original tube, but what if I'm starting with just an engine, like one of the scooter engines? I saw where John O'neal fabricate a coupling device, and that the Thai kit includes one. I don't have the capacity for fabrication, so any ideas would be great, or maybe I'm just missing something that someone could direct me to.

    Thanks.
     
  14. pistnbroke
    Joined: Jan 2009
    Posts: 1,405
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    Location: Noosa.Australia where god kissed the earth.

    pistnbroke I try

    well if you dont have a lathe or a welder then it makes it more difficult but you do have the ability to cut with a hacksaw and drill .. so you must design it within your abilities.... The chain drivedesign I made up could be made without welding using U bolts and remember to decied if you are using a left or right hand prop. the larger and more powerfull engines tend to give the more satisfactory results if weight is not a big consideration.
     

  15. masalai
    Joined: Oct 2007
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    Location: cruising, Australia

    masalai masalai

    http://www.youtube.com/watch?v=OEige-SRBds&feature=related
    This is near perfection for a weed-eater power system... Electric start, Angled propeller - looks like standard parts all in a neat RYOBI package - all one needs to know is the Ryobi model number and the propeller stuff (how it was fitted price and pitch etc)... Why reinvent the wheel when a very attractive solution appears to use 'off-the-shelf-components, - - - MAGIC...
     
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